Definitely go with an instructor that has been there and done that for real. Float flying is still seat of the pants flying, much of what an experienced float pilot will show you isn't written down anywhere. They have usually come from lessons learned.
Keep in mind that both Ontario and BC float flying are different from each other as they not only deal with different terrain and weather, but also different types of water. Flying from a lake is different than flying into a river, or a canal. Or littoral waters. Salt water, fresh water and brackish water are all different due to their densities. Plus salt water and brackish water require additional post flight duties.
Good luck. Also if you want to read some good study material, I strongly suggest getting J.J. Frey's book How to Fly Floats. Since he was the Man at EDO air for many years, he does know what he is talking about.