Great explanations, everybody. To answer the other part of the question about overhead drum mics, there are no hard and fast answers or rules, just some suggestions and alternatives.
I like the MC012s with cardioid capsules for drum overheads, but I also like
the Behringer ECM8000 omni, the Audix TR-40 omni,
the Shure SM-81, the MXL-603S,
the Neumann KM184, and the T.H.E. KP-6M omni. It really depends on the drummer and the song. The Coles ribbon mic is also great for overheads, as are some large diaphragm condenser mics, but I like the sound of the smaller mics. But that's just me.
Kinda like asking about guitars. The Tele, the Strat, a Les Paul, and a Jackson all have different sounds and there's a right place for each of them.