Phantom Monstrosity

Whichever one you burned second, presumably.

According to the RPG, you replace it completely. Brandon's said that there's no canonical way to have two metals besides being a mistborn or involving hemalurgy http://www.17thshard.com/forum/topic/2759-non-mistborn-allomancers-who-can-burn-multiple-metals/ That said, there's an open question of whether this is just a 'canonical way' that takes into account that nobody has any lerasium.

Vin seems to have far more intuitive understanding of her powers, Elend seems to have more brute force. Vin has always been a natural at doing the subtle stuff - far more precise and delicate with them. Even after a year of practice, Elend still can't really stick the landing when steelpushing, but Vin was able to manage it in a couple weeks. We know that hemalurgic spikes don't necessarily grant more power when stacking allomancy onto you,(Zane's spike granted him extra precision with steelpushes), so just being a 100% mistborn seems like it should allow for some variation than just 'strongest in the world with your metals'. You could also be 'the most precise with using your metals', apparently. That annotation I quoted is from the end of HoA, but before Vin takes up the mists at the end, so it could be including her sliver-ness from briefly taking up the well's power, or it could just be something preservation did to make her compatible with the mists.

Well, he can just tap massive amounts of brass at night, and let off all the stuff he doesn't need in a giant wave of heat. Feruchemy protects you from your own power, after all.

Isomere, Vin is canonically at 100%. (Which I guess is due to whatever preservation did to make her mist compatible, maybe?) Most allomancers we see are around 50%

Yes it does, and we just don't know (it'll be explored later) http://www.17thshard.com/forum/topic/3409-old-god-metal-info/

If you became a lerasium savant, yeah. But you'd need to burn and flare lerasium for like, months to get something like that. Since the process of becoming a savant takes quite a long time (and as far as can be determined, requires long continuous burns, not just using a lot of the metal infrequently), odds are a second bead isn't going to make you noticeably more lerasiumy any more than, say, a second vial of pewter is going to make you signficantly closer to being a pewter savant. More lerasium is going to have more of whatever the primary effect is, but remember that becoming a mistborn is secondary - it's a side effect that's apparently not what the metal is really for. Burning additional lerasium might make you slightly closer to being a savant with all your metals, but it isn't like it's going to make you a double mistborn or a triple mistborn if you eat two or three. You might be like... effectively acting as if you were 101% from being more savanty, I guess? Being a savant isn't really the same thing as having more allomantic power.

After all, you aren't getting any redshifting or blueshifting of light, so something funky is happening at the interface.

Skill is involved to some extent, yes, but in this case it's pretty clear that vin is basically just turning up the volume. Note that flaring bronze gives more info than just using bronze normally, and all duraluminum does is flare out your metals in one short, incredibly powerful pulse. After all, if lerasium just made you a better mistborn by virtue of being a chunk of preservation, atium should make you a worse mistborn, by virtue of being the exact opposite thing. It's been stated repeatedly that lerasium's mistborn-producing ability is a hack to rewrite your spiritual DNA. I don't see any reason why it'd rewrite your sDNA differently the second time compared to the first time. Of course, a normal mistborn would be one of those 50% guys, so he'd be basically twice as strong after eating lerasium the first time. Not a bad deal, all things considered.

Marsh said "It took me six months of practice to distinguish pulse lengths" when he was talking to Vin. And he's one of the best seekers around. Seekers *often* become savants without realizing it - and the process of becoming a savant is, well, flaring your metal for very long periods of time. What Marsh is attributing to (in his words) "care and practice" could be just as much the natural consequence of becoming a savant as it is learning to differentiate miniscule overtones on faint pulses. That said, one of the secondary powers included in allomancy (according to the Ars Arcanum) is the fact that it's a very intuitive system.

There's a difference between being able to differentiate between fifty different jazz musicians when they're being played at minimum volume on a single earbud across the room and being able to tell the difference when you've got a full surround sound home entertainment system.

Well, it'd probably make your personality more preservation-warped, like any additional investiture does. And there *is* some primary effect that we don't have any info on. But in terms of 'just being a better mistborn', probably not.

Alloy lerasium and atium together, for 4th of July fireworks when they explode.

Note the 'most mistborn' thing here. Sanderson isn't saying 'all mistborn' here - and there are a heck of a lot more non-lerasium mistborn than lerasium ones. Presumably a non-lerasium mistborn (like Kelsier or post HoA Spook) would get upgraded to '100%', but additional beads wouldn't do anything beyond that, since they're now at full potential. Note that the rpg includes your skill with a metal as part of the metal rating, not just your power with it (which is why you can level up your metals naturally).

I think it would be kinda pointless to redefine what a year is unless there's a darn good reason for it.

Oh, and there's this, which never seemed to get any attention either I think it's interesting that the god metals have some sort of function beyond just the metallic arts.

You need to Awaken the spikes as well, with a command of 'Nyan!'.

Turns out that the old TWG archive has a quite a bit of info that's not archived on theoryland. In particular, I thought this was very interesting Now, it's possible Brandon's changed his mind, since this is moderately old stuff, but, pretty interesting. It probably puts the kibosh to the 'atium/lerasium alloy makes you a feruchemist' theory, at least. Also, this clarified a bit of "Atium's abilities are not entirely explored yet either" stuff. Being able to see more than just a few seconds in the future (if done properly) makes its power seem a little more in line with being a god metal.

It's probably easiest just to link to the theoryland search for lerasium. That said, the feruchemical and hemalurgic properties of lerasium are for later trilogies

I don't think there is enough atium in the entire hoard to become a savant using it. You have to spend something like a couple weeks burning your metals at maximum flare rate to become a savant, and atium burns so ridiculuously fast that it just wouldn't work out, even if you were using all of the atium that was ever produced. Basically, it'd take so much power from the shard to make the atium or lerasium for a savant that you're effectively tossing a splinter at the guy and hoping for the best. If the shard wasn't claimed, the savant could maybe get the whole shard by virtue of having first dibs on it. Kelsier grabbed preservation from Leras, somehow, so who even knows. You're assuming that lerasium stacks linearly, and that you could keep increasing allomantic potential indefinitely. That probably isn't the case. See the 'sliding scale of allomantic potential' annotation - if Elend is at 100% maximum potential, using lerasium to rewire his spiritweb again isn't going to help at all. According to side material, apparently all sorts of nifty things you could do with lerasium that nobody has any idea about - which are probably related to its spiritweb rewrite ability. Note that it's possible to harvest this sort of stuff from other planets too, and that 'becoming a mistborn' is a side-effect of burning lerasium, not the primary one. No word on atium's side effects.

You'd need way more lerasium than TLR had to become a savant. Remember that Lerasium is concentrated Power of Preservation - if you've got a big pile of the stuff lying around, that's a not-insignificant fraction of the shard's energy

It's part of allomantic FTL apparently.

More than just expensive - impossible to get. While TLR knows about the metals, I'm not sure that he allowed for any to ever be produced. Also another quote about the extra-empire areas

We also have no idea what type of axial tilt Scandrial has. Alternatively you could use a ton of brassminds to store up heat during the daytime. A feruchemist might be able to make the trip, though without rare metals food and water could be an issue.

I think people would have noticed if his blade was missing. That said, Dalinar has the thing where his shardplate was almost glowing, and gav had this thing where his blade was almost glowing...