Sounds like a float wing incidence problem..As Mogman said you need 1-2 deg of pos between the wing and float... You can get this by adding spacers to your front float mount, either to the fuse or the top of the float.. As far as your float step goes, you should be close to the C/G... But if it is hard to shift the floats forward, you can still try it at 2.5 behind. I have a Norseman on floats and my step is about 2.5 in behind the C/G and its fine on take-off.. Like my drawing looks like a Caveman did it O well you get the point...