Timeline of Letters

[LiftIRL]

This isn't my usual platform for cosmere posting, but the people I've been talking with on tumblr havent seemed to come up with much, and the groups im in are still in Spoiler Lockdown- something that really interests me is comparing the letter assumed to be from Sazed in the Oathbringer Epigraphs, to Sazed's letter in the RoW epigraphs. They seem to generally travel along the same lines of thought ('how is it that i haven't noticed you here', 'I'm still new here and learning new stuff aboutm y previous preceptions of divinity', 'its hard for me to act because of dual shards i wield are in conflict', etc). however the RoW letter makes direct reference to Scadrial and to ruin and preservation, while the first does not, and the level of cosmere awerness between them is wildly different.

This means one of two things- either it gives us a better understaning of the timeframe between their writing and of Sazed's increasing cosmere awerness over the years- suggesting the two letter belong to two mistborn eras and perhsaps even helping finally put them in relativity to the roshar timeline, cuz the "find me a sword to represent me, someone who will protec and destroy" brings Waxto mind for me- OR we were wrong in the assumption the OB letter is sazed, and there is ANOTHER DUAL WEILDER in the cosmere. 
What did you think as you read it? Does anyone with more expertise/fluency in Word Of Brandon material know if its entirely certain/confirmed the third OB letter is sazed too?

[Dawnshard]

So I thought that Mistborn era 2 was after the first 5 Stormlight Books so the letters are still both written by Sazed but before he crafted Wax.

[Hayama]

3 hours ago, Dawnshard said:

So I thought that Mistborn era 2 was after the first 5 Stormlight Books so the letters are still both written by Sazed but before he crafted Wax.

The letters don't have to be written during the books we see them, do they? So he could have written the RoW letter during Mistborn era 2, or maybe he even has had an eye on Wax for a while before the events of Era 2.

[Kingsdaughter613 she/her]

6 hours ago, Dawnshard said:

So I thought that Mistborn era 2 was after the first 5 Stormlight Books so the letters are still both written by Sazed but before he crafted Wax.

I’ve noted the timeline before; Palm should be looking for/have found Wax at this point. They were together for about fifteen years before the W&W  books started.