There are no hard and fast settings.
The initial starting point "H" and "L" are 1.5 turns CCW from lightly seated.
The"T" adjustment enters here too (idle speed) and there is initial setting without a tach, depending on age may not be any initial "T" setting.
The "L" needle is primarily idle performance (not speed) and acceleration to full throttle.
The "H" is mostly performance at speed, but all are interconnected.

Fresh mix of fuel. Put ALL of the old mix in any 4 cycle and start new. I suggest 50:1 regardless of what your manual says. This is the best performance adjustment I have found.
Carburetor Adjustment by Madsens.com
http://www.madsens1.com/saw%20carb%20tune.htm

• CW is leaner; to lean will destroy the saw. If over tightened closed (CW) the adjustment screw faces are easily marred; marred adjustments are difficult to impossible to set properly.
• Clean the air filter; adjusting with a dirty filter can cause a run lean condition once cleaned and the saw run.
• Clean the spark arrestor and muffler; if the saw cannot exhale it cannot inhale.
• There are 2 wav (sound - idle & full - may not be highlighted) files that I find most helpful, I think you will too.