Well, I've never flown off water, although I'm dying to try. By the way, use "floats" instead of pontoons. Not sure why, but it's the common term.

From all I've seen, heard and read, there's nothing terribly difficult about it, and some DO consider it easier because you can land pretty much in any direction, so there's no crosswinds to deal with. It seems that a light surface chop is preferable to a mirror flat surface on the water. If it's too flat and calm, the floats tend to "stick" to the surface making take offs more difficult.

You'll want the "step" on the bottom of the float to be pretty much right under the center of gravity, and the floats need to be approximately 2/3rd's the length of the fuselage.

Not a lot of info, but I hope it helps.

Have fun, I'm hoping to get something on floats this year too.

(Oh yeah, make sure you have a boat handy, just in case. )
Dennis-