Air stratification (on purpose)?

[Frstuttit]

Hi
My church sanctuary is 60x35 by 35 high. Older building in NJ so split minis would work well.
Wondering is it possible/practical to only condition the bottom 10ft of air space by using low wall cassettes instead of high wall and sizing the units by that air volume or do you have to size to condition the entire volume of air space? We liklely only need them about 12 days at most a year.
Thx
Fr