I use a hoop...think it's 18" round hoop, I baste them
in first..just like you were going to set at a quilting bee
and quilt. Baste about every 12 inches both ways...big
stitches, just too hold it all in olace. Then start at the
center and quilt out, in case it was not stretched quite as
tight as you thought. The hoop helps everything stay in
place. Mine does not have a sag in the center, but it is
not real, real tight in there either...enough that you can
rock the fabric back and forth on the needle. I do king
size, also, but as you turn the hoop around this way and
that you have to reach down and help that part that hangs
out of the quilt move around or it gets twisted up. It's
just heavy to move...needs a little help. I wouldn't do itany other way.