What planes? Do you have them now? If so, I'd suggest getting or building some floats and putting them on one of your current planes for starters. Major reason is that I had a plane quite like the one you mention for my first float plane and found it to be a bit of a handful with a bit higher wing loading and sensitivity to CG adjustments. You will love float flying, buit the first flights will have your knees knocking - seems that it's just knowing that you can't simply walk out to the plane when it stops or prangs - so the simplier you make it the better.