ok, so im designing my box for my truck now, and its for two jl w6v2's

i'm going with a sealed, downfiring box, with seperate chambers. i have tried

to get the most space, and right now i can get 0.818 cu.ft. (jl recommends .5
- 1.0 cu.ft.). my question is should i stick with this size, or lose some space

by using two braces. by using the two braces the box volume will go down to

0.743 cu.ft.

should i get all the airspace i can? or sacrifice some by running two braces?