PRS nuts aren't plastic. They're made out of a material similar to a Graphtech trem Nut, but you're right they're too blocky I'd like to see them shaped and finished as well
I like option 3 however I think there's a limit to how many items you can have in a poll. You'd have to group them and then have a vote between the winners of the groups
I use CA in the whole slot on my fret jobs, if I get some on the face of the baord I wipe in the direction of the slot with an Acetone soaked rag BEFORE I press the fret in
I just Measured the hipshot trem I have here and the block is 1 5/8". Add this to the thickness of the spring wire and subtract the amount of recess for the trem spring cover and I'd say no thinner that 1 3/4" for the body thickness unless you mill the block down