I deal with this exact same situation on one of the boats I manage for owners that rarely use it (since new). A 2006 27' whaler with Verado 225's. It has a 200 gallon tank and I ALWAYS put fuel stabilizer in it that also treats ethanol, although the marina I fuel has no ethanol. I use either Gas Medic, or Pri-G and have had zero issues with it.
The boat has a 200 gallon fuel tank, I keep the tank between 130 gallons and 70 gallons. I put in 50 gallons of fuel about every 4-6 months to get it back up to 120-130 gallons. We have not had any issues. I run the engines for 30 minutes every 2 weeks on the lift and put a light load on them......in gear to about 1800rpms, and once a month I take the boat out and run it at cruise for about an hour........problem is, it burns NO fuel. To run 3 miles out at cruise, troll for 5-6 hours, and run 10 miles or so back, you burn 15-20 gallons all day. But to date in over 5 years I haven't had to change one fuel filter(they get changed annually with the service) or had any other fuel related problem.