I used rapid rivets. It seemed most other threads I read at the time recommended rapid rivets or 1/4" pop rivets - which I bought but then realized that they were too short for the AP belt and thicker ABS, so I used some rapid rivets I had on hand. I would use rivets to make sure the belt stays together. Mind you, I have no plans of cleaning my canvas belt.
Hopefully this link works. Here is an original. Looks like a single cap rivet. This is not required for any level - just a screen accuracy thing.