Lynn,

Typically people use extended float fittings at both ends (float and fuselage) so that you can move it up and down in the other bolt holes to adjust it wherever needed. But the way you are describing yours with using shims, I can't see why that wouldn't work just as well.

And yes, I agree it is much more difficult to be able to adjust the step location. I've seen people use a c-channel mounted upside down to the top of the float (usually attached to the area where the spreader bars are) so the struts could be moved to different bolt holes in the c-channel, allowing the float to be moved fore and aft by just moving the strut fittings in the bolt holes. If you can figure out a way to do that even temporarily until you are ok with how your airplane performs, that could save you a lot of time and frustration (and probably money because you won't need to cut up so much strut material). Once you know you are happy with how the floats perform, you can always make a permanent fitting for attachment.

Half the battle with installing floats is understanding what you are trying to actually accomplish. And from what I'm hearing from you, you are most definitely on the right track

Paul