I believe the larger Saito's take over a gallon of fuel, according to some. It depends on how reliable you want to be. I do not want to dead stick if I can help it. In my experiance you could fly the plane after a couple of tanks, but it seems there is a period sometime after that where it becomes unreliable. Even the compression can get weaker as the ring shifts, the engine is operating in differant conditions, or needs retuning as it breaks in. An engine, not even ABC is completely broken in after a couple of tanks. A ringed engine will improve over a few gallons of fuel. So it just gets down to how reliable you want the engine to be.