I don't understand why you did vertical installation of video cards. Thermal pads on these video cards do not emit liquid.
I designed the rig to:
1. Maximum air space between cards.
2. Have a taller narrower form factor. (Makes it easier to pick up and move not having to bend down so much.)
3. So I can comfortably fit 8 cards in an area where normally you would only have 6.
...and finally because personally, I think it looks more bad-ass!