Well, I'm putting up my wall panels and just wanted to update everyone with how they're holding up. Of course, it's very early and the real acid test will be 10/31 but ... so far they're doing fine.
My garage is 8 and a half feet tall and I'm making panels that are 7' x 4'. I'm using 1x2s and am stapling cardboard to one side. For several panels, I may end up covering the back side as well.
To secure the panels, they're each tied to 2 hooks coming from the ceiling, and those hooks are screwed into studs, not just the popcorn tile stuff. Each panel is also screwed into the flat side of a 2x4 resting on the floor. Plus, panels that are side by side are attached via 2 zip ties. I'll also brace perpendicular tiles via corner braces on the tops.
I'm having a hard time finding big boxes, but a few furniture stores told me this weekend that I need to check in during the week. So, at the moment, most of panels have faces that are 3 or more boxes.
The panels all seem pretty secure, despite a somewhat flimsy appearance. So far, I find them to be much more stable than what I've used the past couple of years: pvc 'walls' draped with black sheets or plastic.
So, what you can take away from all this: if you wanna use 1x2s frames with a cardboard face, you'll do fine.