I forgot to mention that I did try to flip the saddle 180° and it collides with the opposite focuser knob.
The knurled end of the knobs at McMaster-Carr are too small for my comfort level. I still want to be able to get a good grip to tighten things down since the whole rig relies on this saddle.
I wasn't able to locate anything suitable at ScopeStuff.
The thread on the current bolt does not go all of the way though but I suppose it's possible to get the existing bolt machined down. It looks like it needs at least 15mm of thread to secure the saddle. I don't have the resources to do it and have never had anything custom machined.
A polar-mounted AZ-GTi is kind of an odd duck but believe me...it will hit. When I was testing inside, I had to kill the power mid-slew to avoid it.
I did some more searching and it appears that both William Optics and Astro-Tech use the same knobs. William Optics uses them on their saddles and Astro-Tech uses them on their tube rings. The WO knobs definitely look shorter than 50mm but I can't find the actual dimensions. I'm not sure on the the AT ones - they also look like they may be larger than M6 threaded.
I reached out to Astronomics and William Optics to see what they say. I was just hopeful that a replacement bolt wouldn't be so hard to find.