After transferring my bridge design to the rosewood blank, I carefully drilled the bridge pin holes and a series of tiny connected holes that will later be chiseled out to make room for the bone bridge.
After attacking it with a sanding drum on a drill press, here's the roughed out shape--I'll begin carving down the sides and edges next.
The next photo shows a straight edge clamped down and being used as a guide so that I might chisel out a straight 3/32" wide chanel for the bone saddle. I couldn't find a 3/32" chisel anywhere, so I bought a crappy cheap 1/8" chisel and used a sanding drum on a drill press to take 1/32" off the width of the chisel. I chose to use the chisel method form the book rather than setting up a complicated router angle jig. So far it's working alright...
Here's the bridge with the saddle slot roughed out. I still need to reduce the thickness of the bridge a little I think and do all those fine sanding / curving / chamfering things, but it's progressing well: