Here's what I do with a 1.60 to get it adjusted properly.

Set both mixture screws to 2 turns out. This is too rich at both high and low throttle settings, but it ensures that your fine tuning is done by leaning both mixtures so that you don't get an engine that is running too fat on top in order to compensate for a lean low speed setting or vice-versa. I've used this method on several engines right out of the box and I usually get an engine that starts on the first or second flip and sets up easily after that.

Prime and start the engine. Once the engine is running, reduce your throttle to a reasonable idle. Now screw the "L" needle in slowly, RPM will rise, when you reach the max RPM, turn the "L" needle back one-quarter turn, then re-adjust the idle (using throttle trim or throttle stop on carb) as necessary.

To get the high-speed needle in the ball-park, move the throttle up to 3/4 or so, the engine will run rough as you will be ridiculously rich at this point. Turn the "H" needle in until things smooth out. Open your throttle fully, then lean out your high speed mixture by turning the "H" screw in until the engine reaches maximum RPM. Do this slowly, and use a tachometer. When you find max rpm, turn the "H" needle out (richen) about 1/8 turn, dropping your peak rpm 200-300.

Return the throttle to idle, and let it idle for a minute or so. Quickly advance the throttle to full. The engine should accellerate cleanly. If it dies right away, you are to lean, turn the L needle out SLIGHTLY and repeat. If it hesitates and "burbles" its way to full power, lean the LS needle a bit. LS needle adjustments are made in very small increments!

Once you get this engine dialed in, resist the urge to fiddle!