As usual have not been on this site for a while but found your questioning very interesting, and the answers. I would not just eye test but check for PRA through Optigen, I would also hip score and FN test. We are lucky that those are the only tests we need to do, my IS needs far more tests than that. Check hip scores and Optigen PRA, FN before breeding, surely we have all learnt enough by now to do these things, as a friend said a pretty bitch is one thing, getting the right matting is another if we want to keep improving our beloved cockers.
Good luck if you decide to go ahead.
Fi