As you can see from the pics that Joe posted,
I only went far enough to get 225 X 50 X 15 Kumhos (7 inch wheels)under there.
The esthetics of the flare shape leave something to be desired......but I got tired !!
Another method is to use a jack (or Portapower) to push the whole fender out (using a suitable buck on the inside of the fender). I have a pic some where......
Ah, yes.....John Blonks 914 from the Seattle area.