Man, that shifter and bell crank....noice.
I took a detour on my 818 that started with a 3d printer and has resulted in a cnc router of my own just because I want to make some of my own parts. I'm not too proud to say that I have trouble conceptualizing parts to do complicated things like this, but with all those fantastic pictures you took, I have a fighting chance. I think that makes your work DOUBLE impressive. I'm also really encouraged that you managed to shorten your cables. Well done all around!