Chris - First off, take my advise and get a bubbless tank. Either a tetra or a Jett. It can and will save you an engine at some time. 4 oz is plenty for a race.

Start the engine and get to high rpm for 10 - 15 seconds. Then using a tach. peak the engine to max RPM. Now richen it up 300 - 400 rpm. Pinch the fuel line briefly and the rpm will peak again. When this "Pinch" brings the engine up to with-in 100 rpm of your peak reading, take off and fly.

You will hear the engine lean out as you pull through the turns and then richen up in the straight. If the engine stutters in the turn, richen it up just a little. If it does not pick up quite a few rpm in the turns, lean it out just a little. After a couple of flights, you will get the needle where you want it.

Good luck!