All things else being equal, positive incidence in the wing will make the plane climb. This means you'll need down elevator trim to make the plane fly level. This will help if you have a pitch to the canopy in down lines or knife edge because the down elevator trim will counter it. That being said, I've never liked more than .25 degree poitive in the wing. My planes have never felt locked on with more than that. However, you mention that you're holding more down elevator than you think you should when inverted. Less positive in the wing equates to more up trim, so reducing the incidence will make that situation worse. My guess is that you're dealing with a CG that is too far forward or possibly a thrust problem. There's a handy chart at www.nsrca.org that can help sort all this out. Just remenber that every change is relative to where the plane currently trims out and that adjusting the CG changes everything. Hope this helps!

Verne