Hi, I'm a beginner, working on open chords. My fingers are big, and I don't have trouble pressing two strings with one fingertip. It's much easier for me to play the A maj and B maj with two fingers (and nearly impossible to get 3 in there), but Lisa stresses using three in her course. Is there a reason to struggle mightily to do it the right way (like suffering from a bad habit down the road), or can I, essentially, barre two strings safely without hindering my progress?