well i dont have a guitar amp but the way i'm thinking is that i couldnt give a shit how loud it is, as long as it is around its excursion point properly and it sounds good! and obviously not too too loud that the cab is distorting... but i think you really need to have quite abit of loudness to it wen recording to make it sound big. my guitarist once had a pedal that would make the guitar amp sound as if it was really loud when it wasnt that loud.