I've cut dark slides with an x-acto knife, but a band saw sounds good. No reason you couldn't paint new numbers on, that should work. I don't know if grafmatic septums will work in a bagmag but that is easy to test. There never was a graflock bagmag. I used to have a 18 septum bagmag but like a fool I sold it. They are nice when you have one in good shape. I have a 4x5 and a 3x4 12 exp versions now.