Can I do better than a Zpacks Solplex?

It looks like there is quite a bit of space between the inner mesh and the outer on the rear side of the solplex. Of course this could be used for extra gear stash, and more importantly allows for lots of ventilation. But do people feel this amount of less usable space in the design is really justified?

I would not say it's wasted space. It's probably necessary in the wind and the rain to have the added space between you and what's blowing under the tarp. I guess it would be handy to have a zipper so you could stash things under the overhang in the back and get at them easily from within the tent.

I was out last Saturday night, close to home. Light rain most of the night. An ocasional drip around my head. Guessing from condensation from my breath.
Duane