Wondering if you have had any luck yet. I love running them on pressure with a hard tank. I have only used a one ounce tank, though. I have had my best luck letting the engine run long enough to warm up, tilt the nose up about 60 degrees then lean it out to a slightly rich setting. The pressure keeps the fuel flow pretty steady. My tee dees (.049 and .051) have an aluminum carb body, bored venturi, hole in back plate pressure tap drilled with a #70 bit and Galbreath head with Nelson plug. I run Sig Champion 25%. I like to use an APC 5.7x3 that I cut down to a 5x3. I don't know what kind of RPM I get in the air. But, it is enough to have broken the crank pin. Good luck.