My picture frame did not fit really nicely. It had its gaps. Now, I am used to furniture. If furniture does not fit well I tweak it a little. With picture frames it is another thing completely. As I said, when I laid this thing out I had very primitive tools. But when I was a lowly Officer Candidate in the U.S. Air Force there were three possible answers to any question: yes sir, no sir, no excuse sir! In this case the correct answer is the third -- no excuse, sir. The frame did not fit.
Fortunately it came to me that I was neglecting a VIT (very important tool), namely the miter gauge (Britons read mitre gauge) that came with the bandsaw. This is just a very large protractor.
Here is the new jig in action:
But on to successes. The carving process left gouge marks all over the place. So I ground up a form tool out of a piece of old hacksaw blade. I collect old hacksaw blades for just such a purpose. I made a paper template, ground the thing on a Dremel tool, and adjusted as I went along.