It's a lot better to move the cowl. And that's easy. Simply fill the holes that exist in it with epoxy. And then drill new ones slightly ahead of where the others were. While you're at it, you can reinforce the area around each hole and you wind up with a lot more servicable cowl attachment.

However, 1/16" is more than enough clearance. If you've got the cowling securely attached, that clearance is on the big side of perfect.

If you are seeing some rubbing in flight, you need to add another cowl screw or two. That clearance shouldn't allow any rubbing at all, ever.