I realy dont believe that .5 deg. will cause a problem on a Bipe . Maybe on a more efficient airfoil monoplane , but not a problem on a Bipe .
I try to be a perfectionist when I build and set up an airframe (mostly bipes and Cap 232 ), but I wouldnt waist a lot of time on only .5 (1/2 degree)
on one panel only....
Now if you have .5 + on one panel and .5 - on the other I would try reduce the warp .
More than likely your concern is in the leading edge sanding , this will effect incidense measurements ,not necessarily the actual incidence itself..