Ring belts really aren't good for anything outside the faire, IMHO. They aren't even period appropriate, they loved buckles in the Middle Ages, and they knew how to make them. But you can still have the tied look, because because they did do that. The belt was long, and after it was buckled the excess was tied off.

I wouldn't trust a ring belt to hold up my greatkilt, either. I'd be afraid of it slipping.