search with seaplane rating.
Scheble or Sheble Aviation is the one I remember. Don't think Florida..
searching on Google will also yield more results if you use 'seaplane'.
The thing with ratings and student visa, etc etc.. You know, perpetual bureacracy. One should go on visa waiver only for hour building (ie not towards rating etc).
Some might argue that it's just another rating within single engine.. Hmm..
Just don't take Yanks' word for it as they don't know much unless working in M1/J1 school...
Also, rating on a 'piggyback' papers are only valid when your full non-US lic is according to what I've read here. It's all around on PPRuNe..