I run a 2.5x5x7.
I know your space is a bit larger, but,
In my space I run a 320XL from HLG, if I really wanna crank it I have another 260XL I can use alongside it.
If I had to light your space Id use 3 or 4 260s, maybe XL maybe not, depending on fit.
But that's just me, and I like QBs.