Sorry Phil, there's nothing there that I really want. I am slowly working on a 12" refractor (collecting glass). If I were you, I would hang onto the flat if it is a decent flat. you can check it by testing it with a Newt. or other mirror and see if the figure changes when you reflect off of the flat. The polarizer test isn't hard to do. Just see how the polarizer null appears with the glass in the light path. See the ATM book by Ingalls (if you don't have a copy, I recommend the reprint by Willmann-Bell) which shows how to do the test. It is simple.