i can’t play because i spend VERY little time and effort learning. as i said before, i’m more of a collector. as far as your example: .012 is considered medium/light for an acoustic. if you changed them to .016, the guitar would need adjustments to make up for the difference in tension. all guitar necks have certain amount of “bow” to them. the gauge of strings (and tension they provide) is a factor in this bow. Changing the gauge of strings (drastically, going one gauge either direction has minimal effect) changes this tension, which changes the amount of bow in your neck. the change in bow changes your action and intonation. if you know how to make these adjustments without making things worse, great. if you don’t, then bring it to someone who does.