recording 2/3/4 amp setup

You should mic each amp separately for starters. Then you can mix the sounds together and pan most of it to one side and keep the bass toward the other side, or pan each amp to its own side. This really is more if you're using a different amp for a different voicing. If the amps are of similar voicings you can slather one with effects and keep it to one side and a dryer signal to the other side.

But really if you were to have a mic centered between the cabs picking up both tone simultaneously, you can get do it that way too. That would work a little better if say you were recording your guitar by itself in a room without other instruments that will bleed into the mic. Example: I did some recordings with a band I was in and we recorded the drums and bass by themselves. Then I did my guitar track alone too. You could even throw 2 mics, EQ'ed differently, in front of the amps a foot or 2 away and go like that.

Basically if you're tracking the guitar by itself without the rest of the band you have much more leeway as to how you can mic everything because you won't have other noise entering the mix. People who run studios have several techniques as to how they mic, record and mix and they all work. Try a few options out and see what you prefer. And even if you do just use a single mic centered between 2 amps, you'll get a decent result pending you can isolate the mic with a shield if you're recording with a band or tracking the guitar by itself. -S

Edit: Especially when beginning a new endeavor, the simpler you keep things the better. When you develop an ear as to what seems to sound or work better while recording, thats when you can have a better understanding as to why and how you should move the mic over, or pan something or add this or that etc.. Its all really trial and error until you find your own likings. I wouldn't split hairs over every little thing when in reality you're not going to necessarily hear a huge difference between different ways of mic placement and remember you can always EQ different setups to sound similar at the end of a project. It is cool to try different things out, so definitely be open to that as well, just don't go overboard or think there is only one way to do the job!

Hi I am not sure of your recording situation but when I record my rig I use Palmer PDI-03 Speaker simulator for each head and mic each individually. Them bring them to protools. Once recorded I play with the mix. So I guess if you are working in a pure studio environment what works for me is using the Palmer PDI-03.
Cheers Ron