Modification Apprehension

Out of the numerous band shirts I've managed to amass over the years, these ones are in need of serious  modification. Why? They are all men's size large or extra-large, which leaves me swimming in extra fabric. I've had plans to modify several shirts for some a very long time now, but can't seem to find the time required, or get over the apprehension at potentially destroying a shirt and creating something completely unwearable. I think a few of these may be a project for this winter...