I know a 4 stroke is more fuel efficient than a 2 stroke, but since a YS 53 is about the same power as a Saito 72, and a saito 72 is ALMOST twice the size of a 46, I think you can see where the fuel consumption would be the same. I would send you a YS to try, but I can't figure out how to attach things to emails on this board! :-)

I prefer the 6 ounce tank myself in all honesty. It gives me the extra reserve I want in case some student is hogging the runway when it's time to land. I put it on the side opposite the engine all the time though. I balance it so that it's laterally balanced at about a quarter tank. This gives me the most bang for the buck. I am fairly close to lateral balance from half a tank all the way to empty. Even the weight of the empty tank can affect lateral balance, so even empty, it will help compensate for the motor. You can also fit a bigger tank easier, and get it even more forward so that your needle doesn't change as much from full to empty and level to straight up. An Ultimate Fun Fly was my first "fun fly" type plane, and I put the tank on the same side as the motor. Since then, I've had quite a few, and have decided that the tank belongs opposite to the motor for many reasons.

Jim