My understanding is Tailmaker required a 30 degree endmill and mounting the boards at a 15 degree angle — if the program is truly no longer available I’m sure we can work up something similar. I’ve been working on a couple of alternatives though which don’t require such a fixture or a vertical fixture as is typically used — wrote one up in the Lounge, it’s a blind miter w/ hidden spline and allows one to cut with boards flat. It’s not optimal though (not void free and the ends if modeled are possibly viewed as sort of sexual which I worry about, and there’s an aspect which doesn’t make for a strong joint, but modern adhesives may ameliorate that adequately).