Firstly: Armstrongs were favored because the necks were near-flat, which made them good for open-tuned slide guitar, as can be seen in your Wood, Perry and Georgia whatsis photos. Certain old Supros are also favored, for the same reason. Believe it or not, it's difficult to find anyone to make you a flat neck, it's a full-custom order. (There is a sneaky work-around, involving LMII's preslotted fingerboards).
Secondly: the enemy when working plexiglass is HEAT: boy does that stuff like to start melting, stinking, and totally gum up sanding devices. This is going to totally date me, but when I was in my guitar infancy there were very few makers of solid, heavy picks. Seriously, all you could get were the Herco nylons out to 1mm and the Fender extra-heavys which were no more than a mm themselves. So I used to make my own out of 1/8" plexiglass, with a hacksaw and a drill with sanding disk, clamped in a vise. I made enough of them that they were actually usable as legal tender, I got into a pile of concerts with a pocket full... Then Jim Dunlop came out with both the glassed-nylon Jazz IIIs and the "Tortex" line, which sunk my boat. My wife at the time seemed actually happy to see a reduction in plexiglass dust.... :icon_scratch: you're going have FUN with that stuff.
