yep I would just stack them.
I tried vertically stacking my Duallies when I first got the Faital one. It was...precarious.
They are a bit lacking in depth, which was a selling point to me, as it fits in my car.
The bassic has those big plastic locking corners. I want to get little metal ones to match the dually so it's less awkward.
Also once I can swing the oeavey ipr2 3000DSP my rack setup won't be heavy at all so should be stable.