So, it works. I'm waiting on a few small parts to finish the installation but I did end up installing the neck this evening as sort of a test fit. I still need the correct nut and a new stud for the damn ZR tremolo. I mean seriously, they need to be of higher quality material.
I also took measurements of both necks, most of which are readily available on the internet. I also compared it to a square heel S540 neck from 89. Very similar except for the width. The S540 neck was about 55.5mm whereas the RG1570Z is 58.
One interesting thing is the Indonesian neck wood, at the heel, is 1mm thinner than the RG in the same spot. But the fret board is 1mm thicker. So it all evens out.
There's a bit of "overhang" on the high E side, on the back of the neck, where it meets the body. Not enough to be of any concern though. I pulled out my S5470 and it has the same overhang strangely enough. Cost saving measure?
Here's the neck pocket and back of the Indonesian neck.
Heel comparison, they're pretty much identical. Screw holes are in identical places on the neck.
S5EX1, 540S, and RG1570Z, notice how dry the Z's fret board is. Yes, I oiled it tonight.
Put a mirror polish on the frets.
Oiled vs. non-oiled. I use bore oil.
Power Cosmo tuners installed. This may be a temporary thing, haven't decided yet.