Twin Engine Motor Height

[tunacious]

I am thinking about raising the motors ( twin engine ) on my 23 scepter and would like some input from the experts. Motors are Suzuki 140's and currently mounted in the top hole. On the outboard side of the engine, the ventilation plate is about 2 inches below the hull surface. On the inboard side of the engine, the ventilation plate is even with the running surface. This is because the inside is on the lower plane and the outside is on the center plane. I'm thinking I can go up two holes and go to a 20 or 21 pitch prop. My main objective is to improve my fuel economy.