You can start with both needles at 1 1/2 turns out. The LO speed adjustment should be such that when you throttle up the engine there is a smooth transition to full throttle. If it bogs down it is either too lean or rich. At 1 1/2 turns you can turn the needle in 1/8 turn at at time to get the correct (smooth) transition. The HI Speed needle: after a smooth transition to hi speed the engine should run smoothly and not hot. If you continue to turn in the HI speed needle the engine will (at some point) become lean and begin to loose power. In that case (should it happen) turn out the HI speed needle untill the engine is running strong again and then turn it out about 1/8 turn more, for safety. Hope that helps.