This is from Bob at DLUSA:

The average mixture settings are 1&1/2 turns out for the low speed circuit , and 1&3/4 turns out for the high speed circuit . Carburetor mixture adjustment starts with the low speed circuit. The low speed should be set such that the transition from idle to full throttle is smooth, even if the throttle is snapped to full. This will likely result in a slightly rich idle mixture but you're better off with that than a rough transition. If the engine dies when the throttle is advanced, the mixture is likely too lean. If the engine stumbles when the throttle is advanced, the mixture is likely too rich. Since the low speed mixture has some effect on high speed mixture, always adjust the high speed after adjusting the low.

The high speed circuit is properly adjusted when the engine can reach maximum rpm while in the air, which is usually slightly richer than when its on the ground. A general rule of thumb is to richen from the maximum on the ground rpm by about 200rpm. If ever the engine slows or dies while at full throttle, the high speed mixture is likely too lean and you should adjust it as soon as possible or damage can result.