Nice looking boat.
looks like the factory speaker locations will work very well for sound.
would STRONGLY suggest not putting 6x9s under rear seat this can only hurt
the sound.(the factory placement is good for the 6.5s)
I am assuming you want the 6x9s to try and get a little more bass?
As this is the only thing that they may be better at than 6.5s
Since you are going with a sub the crossover setting to your highs will most likely be set to highpass nullifying this theory.
The sub will handle the lows.
Get good 6.5s and you will still be able to put pleanty of midrange to them.
Not a fan of RF or Alpine thats where you would want to talk to Roz he should be able to get the equipment for ya at half price or less. :rollside:
For the type of system you are describing one 5 or 6 channel amp would be fine and draw less from batts.
Would still add another batt perco.(like a stinger or oddesy 1700)