Thanks for the tow info...
Re: filters. I am a big believer in filters.... besides the ones on the engine itself; I have always liked the RACOR style see thru bowl. It allows you to drain water on the fly if you have to. One for each engine. Change the cartridges every 100 hours or each season.
Other tips to reduce fuel problems are:
Dump a couple cans of dry gas in there a couple times a year (esp. when storing boat for the winter)
When storing long term keep the tank topped off (reduces condensation on the inside of the tank) and make sure you have some conditioner in there
The engine companies also have some decent products on the market for fuel conditioning. Most of them are basically alcohol, which as you know mixes with water (
) and then can be burned like fuel. (As long as you don't have too much water in there)