You could move the wing up in the fuselage toward the center line to even out the vertical CG, and it would probably fly just fine and stunt OK. You could also out in some dihedral in the wing to even out the vertical CG. Just put in enough diherdral to get the leadout guide where itwould be if you moved the whole wing mount up. I wouldn't worry about making the inboard wing any longer, but if you did, 3/8" to 1/2" would be fine. The SIG Fazer flies just fine as a control line stunt model. The kit instructions tell how to make the conversion. Saw several of them used in the intermidiate and advanced class at contests through the years.
Type at you later,
Dan McEntee