Good Question.
I'm not an instructor but I do flog about in an aircraft at altitude with a fixed pitch prop trying to go as fast as I can so I have a bit of operational experience I guess.
a. and b. I guess could be classed as much the same.
2nd question is a bit tricky, you probably need to know the particular engines build tolerance for high RPM low MaP.
Some don't seem to mind it too much ie. TCM O-200 in fact they're often operated well over OEM red line speeds, that is not to say it's ideal for the engine.
And others don't handle it as well, ie. PW 1340 radial.
Often one of the issues is ring land wear due lack of combustion pressure. (In fact there is some evidence to suggest that the over square wives tale started out as an under square rule for radials).
Balancing reciprocating loads are often sighted as another reason against high RPM low MaP.
But really it something which is likely to be somewhat engine specific.
Hope that offers a bit of insight.
Last edited by Obidiah; 20th Sep 2010 at 09:18.