Not sure if this helps, but we have a WoB that Hoid uses Feruchemy to know where to be (thanks Vauric for the links). I would say it's not much of a stretch to say he's using Chromium specifically (he may even be Compounding, assuming he burned his Lerasium bead). Which kind of answers your question: It allows you to know where you could be, and if you go there you'll get lucky (but you can't decide what form that luck will take). When storing, I'd assume you lose that "sixth sense" of when something is right/wrong....
Just speculation (and I know the effects of tapping/storing according to my theory don't match each other like other Feruchemical metals), so feel free to chime in/bash it to pieces
