You know what I do to test fly my plane on the ice? Find the lake with the largest expanse of brackish water that no ice fisherman would be caught dead on (I'm thinking of the lakes around Centerville), and find a nice back bay there where the snow hasn't been touched. The good thing about those lakes up there, they are surrounded by reeds hundreds of yards deep, so you have a lot of clear fly over area. Woth the snow coming down today, I think you should be able to do your test flights once the snow stops falling.
Good luck.
Curtis
P.S. My curiosity was with the incidence. You checked this several times, and I assume you took it from the top of the floats to the thrustline of the airplane (not the bottom, or the wing saddle). Best of luck, these problems are not fun.