OK, I don't have any pics and I'm kinda pressed for time right now but here's a quick overview. It's really a simple process.
I remove the old grips and install the backstrap and trigger guard just as if the grips were on it. Then take piece of cardstock or light cardboard and place it behind the grip frame. Trace the area inside the trigger guard leaving a little extra room where the main spring has to move. Cut out the shape you just traced and transfer the shape to a block of wood cut to the same thickness of the back strap. You might have to sand the block on a flat surface to get it to the exact dimension needed. Take a piece of wood intended for the outside of one side of the grip and trace the outside profile of the grip frame onto it. Cut out the shape from the block leaving at least a 1/16 inch extra everywhere except where the wood meets the revolver frame and the top edge of the grip frame. This angle where the main frame and backstrap are screwed together is important. It looks like 90 degrees bit it's not, and it's different on each gun. I start at a little over 90 degrees and hand sand on a flat surface with the sandpaper glued to the flat surface and run the wood back and forth over the sand paper until the right angle is achieved. Sand a little and check often. After one side of grip is done then perform the procedure on the other side. (Trace, & duplicate the angle).
You should now have the 3 pieces you need. Now set the center piece inside the grip frame and glue one of the side pieces to the center section. Keep the center section positioned against the bottom and front of the grip frame and the outside piece snug against the frame and the top of the backstrap while the glue sets up. Small clamps and some painters tape will help keep things positioned. When the first side is set then glue the other side in the same manner. You will end up with an oversized "blank" that can now be sanded to fit perfectly. If the new grip blank wants to move around a little then glue some shims cut from thin wood between the grip frame and the center grip piece.
Shaping and contouring without damaging the grip frame is easiest if you trace lines in pencil and sand until just a thin part of the line is left visible. Then reinstall the grip and check the fit often. The last little bit of fitting is done by feel.
If you aren't worried about saving the finish on the grip frame you can do the final fitting by sanding the wood down to match the grip frame and then refinish the grip frame by polishing and bluing the parts as required.
