It depends a bit on the shape of what you are repairing, as the difficulty in removing peel ply comes from the fact that it goes very stiff once the resin has cured (so no, I don't believe a second layer of ply would do anything but use more resin). If you've got quite complex shapes, then it can become very difficult to remove the peel ply. If your area is relatively flat, then it is generally quite easy to remove. 

just recieved our rather huge order for some repairs we need to do. initially we were going to try infusion so we didnt order any release film, but now feel we're better off sticking to wet lay and vac bag.