Cool Daniel, glad it had some usful ideas/facts for you.
I am trying to accomodate a 37mm X 37mm chip in a large camera with filter wheel and digital focuser hanging off the side of the OTA - all of which is a large image circle and pretty heavy kit, so if you are only trying to cover a smaller chip in a smaller and lighter camera (like a DSLR) then things can be even easier, simpler and cheaper with a fast corrected Newt
Mike