I made this clips for my PhD presentation, they work fine with A0 format papers or even larger.
They are pretty handy, easy to mount and it's possible to slide the clip along the tube so the paper doesn't crumple. I recomend using high density paper.
I made them to fit a Ø15 mm tube (outer diameter) an I use an M3 screw and bolt to fix it to the paper.
I did some prototipes to find out the right diameter so that the pin grips correctly to the tube.
It also has a gap at the screw so that the screw is more confortable to fix.