re: Yamaha 4 stroke HP vs Fuel capacity

30 gal is on the small side but with the fuel economy of four strokes you should have plenty. I have a 50 gal tank on my blazer with a 150 two stroke and most I ever burned was 34 gallons on one trip whis was 108 miles total distance on GPS.

A 200 on that rig will fly as someone else said, If you can afford the upgrade than I'd go with 200 and not worry about a thing. after running a few times you will get a good feel for what your fuel burn is and how far you can run. Can always throw in a few 5 gal cans if needed. I carried one in my boat for the first month or so until I was comfortable with it.