+1 on the ashtrays. they don't look great but they really do work as well as anything, with a lot less headaches.
when i was in college back in 2003 my friend and i built a wooden frame rig with 2 floating boxes for the 1200s. we had hooks in all four corners plus a large "eye" hook screwed into all 4 midpoints of each side of the 1200 boxes. we threaded bungee cords thru each eye hook and secured them on the corner hooks of the frame. it took some trial and error with the bungees because the center of gravity on 1200's is not dead center. we actually found some bungees of varying length and used the shorter ones on the side that was where the center of gravity was. it worked great in our basement nightclub, except when someone would bump into the booth.
but to make a long story short, the ashtrays work just as well and are portable. of course i only learned this a few years ago.