It really sounds like the sails dont fit the boat very well. Draft at 40% with a rotating mast dont have to be too bad, depending on the geometry. How full the sail is and what the profile looks like on the other hand makes a world of difference.

These sails that have been adapted to your boat.. Is the mainsail designed for the mast? If not, was the luff of the main re-cut to fit the mast? It just sounds like you have a mainsail that dont fit the rig or boat too well.

Any hope of pictures?