I was reading in some of the tuts that you should go ahead and coat just the joints, where you glue tabs together, etc. and also do that in small sections. Doing that you can keep it from warping. After that, you can go ahead and fully coat the thing and then go for the second coat. If you're worried about the warping, I saw a couple of pep pics that had little supports on the inside to prevent it.
Also, let us know how the resining goes. I tried a pep with 65lb. and would be interested in ANY pointers.