In that last update, I had gotten to the point where I was ready to glue on the internal wood strips (kerfing strips) that would hold the side. I eventually got those glued in place. I had some issues with a couple of pieces of it shifting before the glue would hold it. As a result, I had to learn how to loosen fish glue and re-stick the pieces. I replaced one.
trim router and ball bearing collars to allow an exact width and depth channel to be cut.
Rather than try to do this with power tools, like the rest of the channel for the binding, I went for hand shaping the wood. I clamped a piece of wood to the top of the guitar as a guide and used a 1/4" wide woodworking chisel. I cut straight vertically leaning the chisel against the guide to form the back wall of the channel. The flat back of the chisel would form the new back, and I pushed the chisel in a little at a time (no hammer!), then went in parallel to the top from the side taking out small chips to remove the spruce I had just scored with vertical cuts. It's a lot like chiseling out the waste in a dovetail joint, parts of a mortise, or pretty much anything.
This picture is preliminary, before I finished cleaning up the channel, and it's magnified much more than I was seeing with Optivisors on (which is why I took the pic). That step from top to the floor of the channel is 1/16".
Like I say, I don't want to jinx myself, but I'm making progress.