Cleared,
I respect your desire to learn on your own. That is how most of the early aviators got started and pioneered full scale flight. I would like to give you a list of things to consider so that you can make this endeavor the least risky as possible:

Water: Float planes add a fair amount of complexity to taking off. Things to consider: 1. Wing incidence with respect to floats. The Wings should have positive incidence of between 1-3 degrees. 2. Step placement. The step should be even or 1/2" behind the CG so that on plane the CG will sit just forward of the step to maintain proper incidence. 3. Float width. The float stance should be about 25% the wingspan. 4. Prop clearance. The prop should have about 2" under it before hitting the water. 5. Take off distance. You may have to double or triple the distance it takes to be able to successfully takeoff from water compared to land. How much runoff room do you give a full-sized plane in the event of an aborted takeoff?

Air: Being new to R/C planes, means that you don't have a good estimate of how much room it would take to properly fly the airplane. When I was learning last winter, I would use Google Earth to map out how much room I wanted on the lake to fly. Usually picked a radius of about 1000 yards.

Orientation: Just this alone kept me from properly getting into this hobby when I was younger. My planes would last about 15 seconds at most then I would crash. The simulator was an immense help with this.

Safety: Make sure until you feel you are proficient, that there are no bystanders nearby.

Landing: If you can get the plane off the water in that distance, and you can make some good circles, landing will be very tough in that short of a distance. 1 acre will seem like a postage stamp, it would to me. I think I would maybe be able to hit something that size 50% of the time if I was lucky right now and I feel pretty proficient.

Good Luck, this was not meant to belittle or demean, but I wish all the best of luck and want people to be successful with this hobby, because I know how fun it can be.
Curtis