A tip I can offer is to stop pepping (for now). Your pepping skills are great, but I would advise to stop for a while and at least get a few coats of resin on what you have done before moving on to pepping another piece. If you let a raw pep lay around for too long, it will start to sag/warp a bit (experience). That's just the nature of paper; time mixed with temperature changes, humidity, etc. can expand/contract the paper, leaving you a warped piece. If you get a coat or two of resin on the exterior, they'll be in better shape to be left alone while you start building more pieces. I generally build one or two pieces at a time, and follow through until it's at least got a coat of primer before moving onto another piece.
Very good job so far! Keep it up.