Well one of the Hi Roller stands came in. The other is in backorder hell from Adorama. Let me tell you, the high roller is the Godzilla of light stands. Huge and heavy. My assistant is already asking for a raise. I don't think I'll need to worry about the contraption tipping over, especially after adding a few sandbags. It's not going anywhere.
I used a regular C-stand for the other support to test it in my living room. The weather has been nasty all week here so I haven't been able to take it outside. And without two beefy stands I probably wouldn't want to take it out, though even with one high roller and one regular c-stand, it's very stable and easy to maneuver - at least at seven feet and in my living room. Outside and 20 feet up it may be a different story.
12x12 is big, but it seems to be a comfortable size to shoot under without constantly moving the overhead around. Although I haven't tested this on a real shoot yet, I'd think that anything smaller and I'd be moving it around a lot.
An added benefit of going with the huge high roller is I can hang lights off of it without much trouble. Using a grip arm it was an easy matter to throw the Profoto D1 up over the top. Alternatively, I could use a Matthelini clamp (or any pipe clamp with a baby pin) to mount lights directly on the shaft of the stand.
As usual, my puppy is a willing TFP model for all brand new gear:
Edit: Before you ask, it took about 30 minutes to rig this up by myself but I spent about 15 minutes trying to get the frame square with the two different sized stands. With two identical stands it would have been much easier. And I spent another 10 minutes just cinching the fabric up. With an assistant and two identical stands outside with plenty of room I think I could have this up in under 10 minutes.
6 Yes, the wood block method is how you keep from bending the center shaft on the grip head.