Most of the EPA era two stroke stuff has limiter caps, so setting mixture jets is not possible, except in shops with proper tools. Use your ears. On older chainsaws, etc., I still use my ears. 2 strokes, are designed to operate at wide open throttle. Most problems are with carburetor acceleration in achieving wide open speed, or with stuff that doesn't want to idle smoothly for long or at all. No tachometer required in either case. If you have adjustable mixture screws, you set them for smoothest run at high and low speed. IMHO if you can get it to idle smoothly, and quickly accelerate to wide open operation without blowing smoke everywhere, you've done a good job.