It depends how you want to trim the plane. I always trim mine for F3A type aerobatics. This means getting it to go up straight by itself, go down by itself etc etc. This is all a balance of down thrust, side thrust, C of G and wing incidence.

For 3D aerobatics you will have a more rearward C of G which consequently means less wing incidence and/or less down thrust. If you find in the prop hang the model constantly pitches towards the belly decrease down thrust/add up thrust and vice versa.

Angus