Wow, thanks for the link to Texerau. I had no idea a pdf was floating around and have wanted this book for some time. You video looks interesting, especially the part around Ronchi and Focault testing. I have 'Understanding Focault' but have to admit that reading it doesn't give me confidence.

One question I always think about is how much time and effort a "one-time" mirror maker should plan on making to exceed the quality of a generic 8" or 10" F/5-F/7 available from the Chinese mirror makers.

Zambuto seems to imply that whatever magic happens for his mirrors might be in very long, machine driven polishing to smooth out the final surface imperfections that cause scatter. With his retirement and with few mirror makers in the US, it seems like options for buying "high end" mirrors in the 6"- 10" size are very limited. I have been debating an 8" F/7 and would love to just purchase a relatively high quality mirror, but most of the mirror makers seem more taken with significantly larger mirrors.