You need the revolver at hand and that is pretty much all you need. The frame will give you all that you need to lay out the grip profile if you have a picture to work with. I use a bandsaw to rough profile my grips, but after that all the inletting is done by hand using chisels and riffler files and oil, or inletting black to let you know where to remove material.
Dimensions would not get you too far in my opinion when you are dealing with organic curving surfaces, best to proceed by hand with traditional methods.
