Not #3, for sure. Those things are just an accident waiting to happen, especially if you have your hands full when you go to sit on them. They spin, they change height, they're on wheels, and they have virtually no flat surface to sit on. I have one, and have simply "missed" when squatting down to sit on it, landing me on the floor.

Actually, don't get anything on wheels when it comes to holding a guitar. That's asking for trouble. So #1 and #2 are out.

#6, with it's flat wooden surface, will serve as a torture device. You'll end up putting something padded on top just to tolerate it.

#4 is somewhat contoured and probably spins, so that's also dangerous when holding a guitar.

That leaves only #5, and if your going to go with a stationary four legged base and a square padded seat, why not just use a regular folding chair.

After experimenting with lots of chairs, I'm now using a regular folding chair and it works great.

Sascha

PS - Are you seeing this?

How the hell did that happen? There's nowhere to change font size.