Other than recommendations people dont have much more to go on!
Pardon me youngskywalker for attempting to give some advice on this subject.
I am happy for you that you had an experienced sea plane pilot as your sea plane instructor.
But once again may I reinforce the fact that most flight schools do not pay enough money to attract sea plane teachers who actually know their asses from a hole in the water.
So here is one more recommendation:
Before you hand over your cash ask how much time the instructor has in the real world of sea plane flying......then if the instructor is high time find out why said instructor is willing to work for peanuts.