You will have to set up the floats so that the step is about 1/2" or so behind the airplane's CG. My Goldberg Cub will just "rock" back and forth on the step when sitting on a level table, without fuel. You also need a few degrees positive angle of incidence between the floats and the cub's wing...sometimes after you position the floats in relation to the CG you will have to add or move weight to get it to "rock".....

Randy