The only dimensions I've been able to find were in Reaper's DIY thread. I think he said he made his 38" long, with the top being 7" wide and tapering to 14-15" wide at the bottom.
I was looking at making one, but ended up abandoning it. That being said, I was planing to incorporate the field chair so that it would also function as a load hauler and pull double duty.
Have any of you use this style of chair before and if so, does it provide much back support? I like the idea of using crossed trekking poles for support.
I have one if anyone needs some measurements. I have had it for quite a few years, but never taken to the field, it never has made the cut. Works great the times I have messed around with it.
My home built chairs are 18”x55” or so. Half a yard. Support pockets are doubled 3” webbing at the corners of one end, angled so support sticks will cross.
The length is nice to keep your backside and legs clean and dry. We sometimes use them as ground cloths, too.