Backing out limb bolts is a dangerous game. Bolts are not designed to take a bending moment only axial tension loads. There are a couple bows out there that may let you get away with using over-length limb bolts but I would not do it personally and I am sure that manufacturers would tell you no.

I saw a vertical bow by limb saver that would allow you to break the bow down by using the limb bolts.