RE: Would you clear coat - what would you use.
I have used Rich U plans several times and he designs some nice flying planes but they tend to come out a tad on the heavy side so too much paint doesn't help them a lot. Rustoleum paint {most of it} is fuel proof up to a point. The thing I have found with it is you just have to let it dry or set up for about 10 days or more before it really hardens to it's max.
If you really want a tough fuel proof clear coat then go to the Klas Kote web site and have a read. It's two part epoxy like the old K&B paint. The only problem with it is the price!!! The two parts mix 50/50 then thins down at least another 50% so it goes a long ways, you don't need to buy much and it doesn't yellow on you.