Funny you guys mentioned that! After Brandons post I got to looking at things more. One of my buddies has a 60 gallon V tank that would fit under the cabin deck. I could run off that tank first for long runs out and then switch to the main tank when needed. Also I could use the forward tank as a ballast like you said maybe keep it 1/2 full all the time.
I was originally leaning toward 1 big tank for simplicity (less hoses,valves gauges etc) but now I'm starting to like the idea of two separate tanks. Remember John Denver
but I guess thats not an issue with boats
strick