After a week away from the center foot shells, I was able to pay a visit at Mike's, where he had a 12" blade on his compound miter saw that was able to finish the remaining cuts.
As each cut came up, the miter saw was tilted and angled to the required setting. This was a somewhat iterative process, and it helped a lot that we could refer to Mike's finished center foot shell.
I did one cut, but Mike did the other two dozen or so.
In fact, we decided it made sense for Mike to cut an extra set for himself. Some of the cuts were made on the table saw, some on the miter saw.
The end result was just what we hoped for. We still need to cut the strips toward the bottom of the four sides of the foot shells, and we need to cut the left and right sides to put a groove in place, and allow access to the inside of the shell. Hopefully this will continue next weekend.