If it's a real amp, I just let the players tweak the amp first the way they want so that it's 90% there, so that it's outputting "their sound". Then I mic up the amp, possibly make minor tweaks to that tone to try if it makes it better or worse in context, and if it's worse, we will just go back to the settings they had. Simple as that. Usually they either totally know or totally don't know what they want from the tone. If they don't know what they want or they think what they want but don't fucking know how to dial it in, either I'll just dial in the tone, or if they or I notice the tone they dialed in it sucks afterwards, I'll just re-amp it when they are not there. Always remember to record the DI track from the guitar. I forgot to use the DI when I tracked the first album I recorded, the mixing engineer didn't like it, but at least we tracked a good guitar tone, so it wasn't that big of a problem.
What I did with the last session I did was this (band had 3 guitars, 1 drummer and 1 bass player on muso side):
- Day 1: demo vox and one guitar scratch guide track for the drummer, other drum related stuff
- Day 2-3: drum tracking
- Day 4: demo bass, then one take demo guitars with ampsims of all guitarists playing at the same time. Same tone, same settings.
- Day 4-6: guitar tracking
- Day 7: bass tracking
- Day 7-9: vocal tracking
- Day 10-14: mixing
I did the demo guitars, demo vocals and demo bass so that we would have the "full context", so that we would not try to overcompensate the low end from the guitar amp for example.