In my opinion, that gap on the stay is not as critical as the tire to seat tube clearance. You seem to have plenty of a gap there! I say ride along!

The experience I had with little clearance tires is that if you run over a branch, wire or some long semi flaccid object, it can get pull up the tire. Theoricaly, with little clearance, your tire, the object or your forward motion (most dengarouse ) is going to give. In my experience only the object or the tire wins. Besides it doesn't occur that often for me to worry much, specially if you can see and avoid!

Double O