Hi Pedro, My thought is that flaps on this small Cessna is not worth the effort. The wing loading is high to begin with and flaps might add to this problem. And with the added weight of floats and at 8500 feet you will have a handful. If you go ahead with this I recommend that you only us a very mild setting for the flaps when you deploy them. I could send you a couple of pictures, but since Steve will do so I'll defer. Best of luck.