Just an update on this, since it's been like 4 months since I actually did anything. If I'm being honest, it's been closer to 6 since I actually worked on the guitar, the other 2 months was me trying to practice and not really getting anywhere. Life has been chaotic to say the least, and time to spend on this has been pretty low due to it. That's no excuse, I know.
To update the inlay situation, I'm just not happy with it. I can't get this "easy inlay" crap to actually work the way I want it to. inevitably, no matter what I do it has voids down inside of it and you end up sanding through to open up those voids. I got some advice to crush the flakes up smaller, but then it loses the chatoyance in the shell material and just looks like colored dust. Also, if you don't crush it up more, you get some shell pieces standing up and when you sand it smooth...it's not smooth at all. You can feel the "layers" of shell standing up, like you're running your finger across a brush or something.

So...the TL

R is I'm not happy. So I've reached out to my local maker group on the book of faces (groups are about the only thing FB is good for) to see about hiring someone with a CNC to cut the inlay material and the fretboard recess for me. I'm willing to spend a bit to build this part right, it's literally the single biggest feature of this build and needs to be spot on.
So here's where I'm coming to the hive mind for input. Masecraft sells these ALVS sheets -
ALVS Acrylic laminated shell veneer sheets
Anyone ever used these?