The Aluminum exhaust diverter is a good Idea, If you can get it to stay on. I took mine off because it became loose and I started thinking : what if it came off while in flight or even just running on the ground. Im sure it would tear up my main spur gear. If there was a way to probably spot weld it , it would be a novel idea. I just didnt and dont want to take the chance of it comming off while it was running. I may later revisit this idea if I can come up with something that will be a sure hold.
Oh yes, on speeding things up on the curing of the fiberglass: use a heat gun or hair dryer. If you use a heat gun, dont burn it. Heat it a little and let it cool. do it a few times and it should speed things up.