I got a new belt today. After swapping several more, I ended up with one that's 98-5/8" instead of the 99-5/8" one that I had. I'm thinking that the belt still has some slack from being bent up in  the package. It went on kinda tight to begin with, but the tensioner probably helped pull the kink out after the little bit of running.

This new belt went on really tight, but it went on. I'm going to let it sit for a day, then let it run a little to see if there's a scoring mark on the belt at the innermost rib. If so, I will cut that rib off and let 'er buck.