Have you found any mold yet? If not I would let them swell. I never seen a crop mold overnight. Spots sure. If your are seeing mold then do what you have to do. But if not let it ride. Just check colas for little dead leafs twice a day.definatley dont wanna do all that work then have them mold, better have some bud than none.
How much? and do you have link?PS Forgot to say I ordered "by the foot" greenhouse quality covering from Farmtek. Good for 4 years, made for gardening, and cheaper than buying a roll of PVC around here.