Thanks SeamusG, kind and undeserved words.

One more thing: stop the engine each time you adjust the low end needle or air bleed.
This is specially dangerous because it is normally done with a small screwdriver.
The engine vibrations may make it slip into the prop, and into your body from there.[]

Increments or reductions to that low end should be done in very small increments (no more than 1/8 turn); otherwise you will loose perspective of the changes you are producing.