Shouldn't take more than a minute really, as you dial it up (as the motor gets lifted up) it should gradually sound better and better until you hit the wall where it gets too tight which will be obvious, when you meet the wall, just go back a bit to where it last sounded best, trust your feeling
That's the idea but you have to have pinion height above the bevel gear set correctly too otherwise the noise is not related to the meshing but rubbing on the bevel shaft or always being unmeshed.
This why is can never seem to change much or finding the sweet spot is Impossible sometimes