Low ceiling, but want treatment!

Hey gang, I am building a band shed / live room for 90% band practices and 10% recording (though, I'd like to make it work as more of a 50% / 50% eventually, if possible). I'm putting up the last of the drywall and when that is done, plan on treating the walls heavily with 2" 703 all around, specifically in first reflections and bass trapping, but I will be near the point of needing to plan my acoustic treatment for my ceiling. Here is the BIG issue... My ceiling height is currently 7' 1" (or 215.9cm for those using what us in the US isn't :D). Obviously, with this low of a ceiling and no way to increase that space, I'm curious as to what the best approach would be. I was originally planning to just glue on 1" thick 703 to the ceiling itself and cover it in cloth (the entire ceiling). After much research, it seems an air gap is quite important in reducing lower frequencies within the room (where the real problem is!). The floor is currently cement, but may become cork or laminate flooring eventually (for now, throw down plywood when doing any recording.) I obviously want to keep my space maximized from floor to ceiling when it is all said and done to make sure it is comfortable for all. Any suggestions on this? Just glue the panels on and save the ceiling height? If so, what is a good glue to put 1" 2x4 panels of 703 directly to the drywall with? Or devise some type of airgap? If so, how much for 1" thick is optimal (obviously anything over a few inches isn't quite possible. Was hoping 1/2"-1" would be worth doing, if doing at all). Thanx guys, this really helps.

beside the floor-ceiling modes, the next thing is flutter echoes between the floor and ceiling. keep in mind that the modes on the floor-ceiling may require some panel traps etc. i'd suggest measuring the room acoustics to see what needs to be done. the echoes can be stopped by creating a nice checkerboard pattern on the ceiling with 2'x2' squares of insulation covered with cloth and leaving about 6" or so apart (think of centering the 2'x2' on 3'x3' squares). use the 1" insulation on 1" foam blocks to create some gap. not ideal but then again neither is a 7'1" high space... then in the corners, build superchunk traps to deal with the bass.