I think I will go with the traditional 24" again. There will probably be a shallow 2" sand bed plus a 1" starboard. That would be 19" of "usable" height (excluding the 2" above the surface)
Since the big tank will be viewable from 2 rooms I'm going to have 2 different views. The tank will be in the great room, on a stand that is 24" high.
That is the MAx height in order to fit the tank into the wall.
From the sunroom - the floor is 44" lower
So 44" + 24" = 68" off the floor in the sunroom to the BOTTOM of the tank
The top of the tank will be near the ceiling - 94", this will allow 2" trim to be installed. The 2 corner overflows will be blocked from view in the sunroom - 10" on each side. The center overflow may be viewable, or I may install a 10" wide piece of trim to block it