I bought the EAF bracket for Celestron C11 and C14. I have an earlier C11. My problem is the flexible barrel that is supposed to fit on the shaft of the C11 focuser is too thin. It's inside diameter is 21.74mm and the shaft's outside diameter is 22.42. What is the remedy? Secure it to the the thinner part at the top of the shaft? That doesn't seem right, and I would think would result in a wobbly turning action.