If you aim a mic at the sound hole of a Martin style Dreadnaught, it's gonna "woof out". Personally I prefer an AT4033 aimed at the neck/body joint for that. Classical style guitars is another subject all together.
Acoustic guitars. While there is a bit of conventional wisdom, there are SO many variables. for instance I have two Martin Dreads and they sound totally different. And a Breedlove Read that sounds NOTHING like the Martins.
The majority of my amps are lower power (15 to 30 watts). I do use a Tube Screamer from time to time but usually just drive the amp. Above that is too much for me
A subject dear to my heart. I have a couple of combo's I have gravitated to over the years. I like a Royer R10 and a an MD441 or a SM57 I took the transformer out of. Only one mic? The Royer.