I first got exposed to 7 strings around 1991 when George Van Eps came out of retirement and started playing around LA. He was the father of the 7 string and his extra string was tuned to a low A. The low B came much later, I believe when Vai started playing one. Which of these two tuning you use completely changes that way a 7 string functions. After all these years of playing solo chord melody pieces on a 7 string with an added low A, I couldn't imagine trying to play with a B, just as I'm sure, those who are tuned to a low B would find my guitar incredibly confusing with it's I-V interval between the two lowest strings. So which do you use? why? and have you tried both?