Hi all, after 9 months work, I have just finished a 19 inch mirror at f4.5. It appears to be very good on the foucault tester for the central 18 inches, then things go down hill outside of that. But that's OK as I treat the lost inch as a 1/2 inch support ring for the 18 inches remaining of the mirror. I will paint the edge black, and all will be well. I will report back with a pic after the scope build.
cheers, Frank
