First, dont think you need to balance. Lots of well known records after stereo are not balanced--and that depends on if we're talking output level or just instruments balance. The issue is a very basic part of learning mixing. And you dont need anything special! Sometimes if I just want one guitar, like a simple trio, I will move the bass over as a way to balance--but I dont mind the levels I just listen to see if it sounds natural or awkward.
