Wings and horiz. stab skewed
 

A friend has been given a hand me down been to the wars and back (repaired numerous times) 65" span 20cc size profile model that has its wing and horiz. stab perfectly parallel and level when assembled and viewed from the front or the rear, but the diagonal measurement between edge of aileron and front edge of the horiz. stab is off by about 3/8". It is quite obvious to me that to make this right would entail major surgery so my view is that at the best of times profiles are not designed for precision aerobatics so leave well alone and just fly the snoot out of it. I have no idea what sort of flight envelope this discrepancy will give so I would appreciate your thoughts.

With a model like that I seriously doubt you'll see any difference in the performance. Take it out and fly it! Have fun!