Madame Zelda....
My first two quilts ever I quilted in the ditch and used extra high loft batting. What a chore that was!!! I'm hoping to thwart your plans before you drive yourself crazy. If the quilt is for a little person, I would forgo the quilting altogether and tie tack it with worsted weight yarn. If you cut the spare yarn to 1/4 " of the knot and run your hand over it it will fuzz out and the little one won't be able to chew it off. It's much more durable for a child's quilt to be tacked as it will be laundered often and you don't want your pretty stitches to come out. I wouldn't ever machine quilt using high loft batting....Just tooo thick.
JMO
Melissa