kicker motor, hp and location

[sugerbell]

I have an 1976 20ft master angler that I plan to add a kicker motor to this winter. My questions to those of who have experience on this topic, are 1. where would be the best location? 2. what hp motor, I am thinking either a 9.9 or 15? 3. Is there a certain bracket that works better than other? Any other thoughts on this topic would be greatly appreciated. Thanks, Brad