Originally Posted by
ckcowl
If you are having your quilt longarm quilted horizontal seams are best, they lay straight along the take up bar, when vertical they build up turn after turn causing a lot of bulk in the center and floppy edges. If quilting by hand or with your domestic machine they can go either direction.
This is absolutely true, but when the seams are vertical the quilt can usually be mounted sideways on the longarm, making the seams horizontal.