Prop Pitch question...

[Flyby]

I think I understand a little of the prop pitch article, but I'm not all that clear on it as I think I should be. Someone check me out, please. I'm thinking of altitude, and speed situations where I need to adjust prop pitch to either achieve, or maintain performance. For instance:
* I think I need more pitch at higher altitude for biting into the thinner air, and less drag on the airfoils (wings, and propeller blades), especially if speed has fallen off like during a long climb.
* I think I need to decrease prop pitch when I dive from high altitude, as speed builds up, and engine rpm rises ( I'd have to watch, and adjust pitch to keep rpms from over-reving the engine).
* I think I don't need as much "bite", in general, from the prop at lower altitudes where the air is more dense.
* I think all of the above are dependant on tactical power requiremens. That is, whatever it takes to keep the engine in the desired performance regime: Max aircraft speed at low altitude versus max aircraft speed at high altitude: increasing diving speed: takeoff: landing: cruising.
I guess it all depends on the individual aircraft, and knowing your plane, or watching the engine revs. Anyway, that's my thinking. Am I on the right track anywhere here?
thanks!
Flyby out