Another idea to level the table surface with the machine bed is to get thick foam, cut out a space to recess your machine in, then cover with a plastic table cloth or some other slippery type surface so the quilt slides. You'd need to cut a hole for your bobbin/needle area.
This was suggested by someone earlier on the board. If you're going to do a fair amount of large quilt quilting on your domestic sewing machine, this is worthwhile for the ease of moving it out of the way to resume regular sewing.