George, If you lean the Low end, you also need to open the High and vice versa. Low needle supplies fuel right up to WOT.
1 1/2 to 1 3/4 turn open would be ball park for a run in engine.
Other method:
set engine at very fast idle (2200 rpm). Turn the L-needle closed until rpm drop from fastest running. Open the needle 1/4 turn from there.
That would be basic setting.