The top of the stand has a 3/8" stud. You would need a 3/8" to 1/4-20 adapter. I would also want a ball joint so you could adjust the angle of the camera. I guess you are wanting to get your camera high, if so you might consider a Cowboy studio light stand which comes with a 1/4-20 stud. Cost on Amazon was $13.00. You would still need the ball joint.
Personally, I use 4 1/2" clamps, and they work perfectly. It may be possible to get away with 3" clamps, but I seriously doubt it. The diameter of the support bar is large enough that I have to squeeze the handles on the clips almost all the way to get them on the bar. While I still have a small bit of room, I don't think the 3" clips would be large enough.
James it maxes out at 10ft wide. I have a 10x24 ft green screen. It will accommodate your banner in terms of weight, but if it's wider than 10ft you will have issues.. This is not a cheap stand in my humble opinion. I love it. Hope this helps you.
I have only used 10 x 20 muslin and I would not put more than 2 or 3 on it at a time. If you are only going to use one background I think is should be alright. The problem that I had, it tends to tip and it bows in the middle. In my opinion it's not very. I hope this helps.
Yes, but it can easily tilt if back drop is too heavy. I'm currently using a huge Muslim backdrop in addition to randomly overlapping other background and it still stands sturdy. But I am looking to use sandbags, etc. as weights just incase.