I think a lot of long armers do the borders as they go. They have a bit more room to stitch the design than you do with your mid arm. Having said that, I have a long arm and have not yet picked up the knack for this. All that starting and stopping makes my design look jagged. I'm sure that with practice I could get it to work, but right now, I do what you do. take the quilt off and turn it.