If you are going to build a bender tye shelter, here are a couple of tips.
Mark out the diameter with string from a central point, place your poles where you want them as opposite pairs.
Pre make your holes at an angle, so that when poles are inserted they lean outwards. Make sure there is at last a foot in the ground.
Weave branches at least four or five levels around to add strength and keep it rigid.
In the past they would have been thatched with grasses, or covered with hides.
Research wickiups from native American culture,
Also gypsy benders.
To be honest, I'd not bother for camping in, you can do most of your talk without , but you could make the bender/wickiup as a group activity in addition to your talk.
Cover with a large tarp.
6 foot across is a good size for a bender,
Measure from central point with string tied to a stick.
Have made several and lived in one for a few weeks. Several times, Canvass tarp is best, plastic can get sweaty and horrible, especially if it's hot! But fine in winter.
I used a section of old army tent for mine in the end, which also had a window, which was nice as it was awful dark otherwise.
I've built sweatlodges too, and as patree says it's an almost identical construction....don't use plastic or nylon tarps for a sweat! Blankets, only.
Ps, don't forget you need realy long poles, you have a foot in the ground, the tops to be secure need about a two foot overlap with each opposite pole to stop them deciding to come undone if you accidently knock a pole when inside, then you have to calculate the height of the structure, about 5 foot is comfortable enough, but I make mine just above head height at 6 foot, then you have to think of the span, so I use poles 10- 12 feet long.
