Well, here's what I've learned so far:
1. Hardboard (thin cardboard like stuff) makes a pretty good insert between the scales.
2. Use a drill-press, I'm not good enough with a drill to get the holes as round or as perfectly spaced as I would like.
3. Put a piece of cardboard over the blade and properly secure the razor. I can imagine that a half open razor spinning around a drill bit could be more than a little dangerous :gth
4. If you put the center of the holes 1mm below center-line of the scales you can see the bottom edge of the blade through the hole which looks pretty cool.
I drilled 3 holes (9/32, 1/4, 7/32) starting at the end of the scales (furthest from the blade) with a 2mm gap between the hole edges. That moved the balance point just barely behind the pin. Still a long ways from balancing at the midpoint of the tang but it makes a much bigger difference at shave time. The tendency of the blade to want to rotate when shaving the neck is much reduced.
I'll post pictures when I get the holes properly de-burred and re-polished.