If you don't wish to be fancy but cheap, I'd plan on being more versitile & flxable with the medici flats units on the deck, as suggested, rather than attached to a wall.
You can use fixed castors, with a central spigot, into a deck plate. Or even utalise tank traps [boom foot plates] to drop the unit onto. If your stage surface is smooth, you can use old deep pile carpet, glued stapled or scewed, underneath the unit. With the pile sitting on the deck, movement ican be as smooth as a babies backside. Also with just a drop in pivot spigot, the need for a tatt skirt around the bases edge is reduced.
In a number of pro & ameatre converted venues, the removal of the ceiling gyprock or plaster sheating, above the stage area. Will exspose a heap of roof viod space, that can be utalised for the grid. Especialy if it is an 'A' frame roof & the jiosts run across the stage.
However being a new building there may be a lot of objections to you venturing down that track.
In most cases you can achieve weird & wonderfull things, by thinking outside the box & employing the X factor, in creating that wee bit extra space.