Here is an easily implementable $10 solution:
(1) Determine the distance you want between the ceiling and the bottom of the mounted QS4's.
(2) Cut two pieces of 2x8 lumber to that length.
(3) Fasten a pair of L-shaped steal brances on one end ("top") of the 2x8's.
(4) Paint/finish the 2x8's in the color of the ceiling or the QS4 (or whatever you like).
(5) Fasten the included QS4 brackets on the 2x8's, at approximately 5" from their "bottom" -- consult the actual dimentions of the QS4.
(6) Fasten the the 2x8's into the ceiling joists via the L-braces, using long woodscrews (#12 x 2" or longer). For safety, accurately ascertain the joist centers by using an electronic stud sensor.
(7) Hung the QS4's onto the 2x8's.
