Awesome. When I was researching the CZ 101 (still am, actually), I spent some time reading the MAME implementation, including the NEC upd933 chip emulation. I was going to say I'm surprised I didn't find your docs, but it looks like they were all published late last year which is precisely when I was doing my research (I used the holiday to work on some projects I'd been stewing on in the back of my mind, and a phase distortion plugin was one of them).

I don't know why I find that era of synth so enjoyable and interesting, but I do. I love every FM synth, but that side of things feels pretty well covered by existing tools. Korg makes the OpSix (and I have two), Yamaha has the reface DX and I think their workstations still ship an AFM engine, and there are at least a half dozen plugins that are mostly quite accurate, and a handful of other hardware options.

Phase distortion just feels more neglected, so that's the one I've been spending time on. I have an excellent engine running, which is more accurate than the Arturia CZ V engine (at least compared to my actual CZ 101, maybe they were comparing against another model, but the MAME engine is also like the real CZ and not like Arturia, so I am inclined to say Arturia got sloppy), but I'm going pretty slow on the UI. Making a nice plugin UI for a synth that didn't have a nice UI is a challenge. You can't just copy the original UI if you want it to be fun to use.