I like to stitch on a 'taut/firm' quilt, so roll the bottom up with the leader - then when the end is close I do pin the edge.
For pantos or edge to edge, it sometimes depends on the size of the quilt, and particularly batting used. Poly takes up a lot of room in the throat. I have an 18" Tin Lizzie and won't use any designs more than 12" wide. My DDs 60x70" quilt is on the frame now with a cotton/wool batting, and I am lucky to get a 12" pattern into the last row.