Carburator setting question

Wots

Hello all ! Im trainee in Estonian Stihl dealer and currently my master is on vacation so im asking few things to make sure.

First:

If u adjust carburator on saws that have L and H screw then will i should do it by book what says max rpm is 14k(for exapmle) or just make enoughly rich mixture ?

Max rpm WOT depends on mixture as u know.So making it richer decreases max rpms. I simply cant have same rich mixture at 14k rpm if i turn H screw out and rpm drops to 13K(for example).

I hope u got my point. Its so hard to find any good detailed information. Factory service manuals are very general.

Second:

The Stihl 170-180 series saws are most common in our country because they are cheap are good enough for that money. Only thing i can adjust is Idle mixture(turn air screw). So what can i do if i see saw will run at WOT almost 15K rpm? Max rpm is 14K by the book.