I worried about the buckles rubbing, but not a problem after five years. The buckles have a bit of curve to them, and that helps. But they don't work on tighter angles, like the last three towards the bow. I tie those by hand. Also, I don't cinch them too tight, just enough to keep the cover from flapping. It stays on at the lake all summer.
A bigger problem is that the straps are a bit thin for the standard buckle to grip, and don't hold tight unless the strap is fairly straight. I just ordered
these buckles for a new season, and they come with little keepers that I think will help with that. Plus they'll take up some of the loose end.