Might be a bit late reply. I have a set of Clamar 1400 amphibs on my S7 supersport 912is, whirlwind (ground adjustable) prop. They perform really well, although I don't have a ton to compare to. I'm getting roughly a 15-18 sec take off on average when I'm single pilot and about 30 sec when at gross (1550 lbs). I've flown them in all kinds of conditions (about 80 hours), beached, boat ramped, docked, landed on rougher grass runways, they seem to take it all well. Also have had some hard landings and so far so good. They are pretty sticky on glassy water but do eventually release. I do not have a ventral fin and have noticed that I have slight yaw instability, that of course was not present on wheels. Otherwise the plane feels about the same as it does on wheels, just a bit slower. I don't feel under-floated, but again little experience. Step turns are no issue. I can also have two ~180 lbs guys stand on the very aft or very bow (one on each float) without feeling like it will tip over.

One other thing to point out, I was originally building a pair of Zenairs. If you go this route, GET THE PREDRILLED KIT, I did not. I got about 2/3 through one float and had enough. And I love building. The floats seemed to be more work than the whole plane, as others have said. At this point I'm happy I bought and sold the zenair kit.

Specs on my aircraft:
Grove gear and 26 airstreaks: 864 lbs 10.81 CG. Cruise speed ~104 mph with the prop pitched slightly favoring climb. Stall speed 38 mph IAS full flaps (Vgs installed on wing and tail)

Clamar floats installed: 1060 lbs 9.53 CG. Cruise speed ~96 mph with the same prop pitch as above. Stall speed 45 mph IAS full flaps.

Feel free to PM for my number if you want more detail.

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