Sorry, just peeking in here.
Windancer, are you trying to replace the scales and you want them to match up? If so, I'd recommend the eyeball method - the angle guides on most sanders and such aren't scientific instruments, I wouldn't trust them. Just make your scale grossly oversized, cut an angle with good flat-sanding surface (like a disc sander) and then lay the scale and the knife flat down side by side and decide how to adjust. Hopefully you'll get just the right angle before your scale is not oversized anymore. Hey, it's worked for me.
OK, I'll go mind my own business now...
-Drew