KenK, Thank you for the site. Amazingly, this site did not show up when I was "Googling" this morning. I am considering using the cone calculator I found today and going from there. The design will not be a true tipi. It will not have the gap and inner wall for updraft ventilation. I will use a single pole in the middle and many ground anchor points. The funny thing is that it will not end up being less expensive than a tent of comparable square footage.