i recently had a tipi / lavvu made by a good friend of mine and it works a treat , however , being made of canvas its really bulky and quite heavy to transport , ideal as a base camp shelter but forget it for a roaming trip . the dimentions are 3.5 m dia and 2.2 m high so very spacious inside . cant remember the techy bit about how he worked out the pattern shape but i do know it used a semi circle of 235 deg . the front seem / door laces together using willow needles first nation fashion.
sounds good buddy u got any pictures.i have also wonderd about the top of a traditional tipi where the poles come through ,about the rain comin in,