it depends more on what YOU like! the more drape, the heavier the quilt becomes.
What size can you possibly quilt if you do it on your own machine, what size can you hand quilt comfortably, what size batting did you plan to use? What is the largest your quilter will do if sending it to be machine quilted!
So many things to take into consideration.
HOWEVER, if entering in a show be sure to use their guidelines or it might be miscategorized!