I've only modded 84 mm SAKs, Tom, but of all the tools I use for my projects, I'd say the drill press is pretty indispensable. Even just a small bench-mounted unit would do the trick. I'm sure one of the more experienced modders might have some insights for you on the Mod Squad forum.
You'll learn so much the first time you do it. Good luck and I can't wait to see the results.
Myron