If your scrappy is very scrappy (with lots and lots of seams) you might want to go with a larger motif, or one of the widely spaced cross-hatch or diagonal lines mentioned before - keeping handquilting even across seams can be difficult, and frustrating! I know it doesn't show off your stitching very much, but SITD on the ditch side of your squares does make it easy to be consistent....
Alison