ORIGINAL: aussiesteve

Depends on
What oil?
What Oil ratio?
Coleman, Pump, Premium pump, 100ll Avgas or ?? fuel
Which brand of spark plug? (Which brand do you use and why?)

Ok, just in case it is serious, Ralph answered correctly in post 2.
I don't encourage the pinch method on Gassers because many fliers that require it come from a glow background and expect the "instant" result that method gives on a glow engine. If a gasser gives that same result instantly, it either has a problem with the pump or is not tuned right.

I tune high end by tachometer, low by ear, then the rest by minor adjustments whilst flying and reading plugs. I only ever use the tacho again after that if I am changing to a smaller prop and want to make sure I am not over revving the engine.