RE: Corsair Cowl help?
Tony,
I have this same model. When I built this model I did what you did. I decided it would be easier to mount the cowl ring to the firewall, as instructed in the plans. However, I also thought it would be better to screw the actual cowl to the ring. I used four screws, see the picture. After flying this for some time, I noticed stress cracks around the holes, and in my case, I also opened up holes in the cowl ring for fueling and pumping up my retracts. I added fiberglass to the inside of the cowl, but it really didn't hold up. Another reason I did this was due to installing the "dummy engine" which also makes getting to the ring mounting screws more difficult.
At this time, I have purchased another cowl and ring, and glued them together with thin CA. I mounted the fueling and retract points into the fuse, and I even installed the dummy engine back into the new cowl and ring. I had to open up holes in the dummy engine to get to the mounting screws, it is a pain, but works. You can purchase a fiberglass cowl from fiberglass specialities, but they don't sell the cowl ring.
Here are a few pictures of my setup prior to my changes, which included moving to a ST90 from a ST61.