Malcolm, more important than quantity is opportunity. The symposium could always be held where there is the highest density of members if bragging on high attendance figures was of greatest importance. Every scenario of how to do symposiums has merits as well as disadvantages. Weighing one against another is not a simple thing that can be answered by statistics. I would even imagine that symposiums help stimulate the growth of woodturning in the local region. I have been in Phoenix in the summer on a few occasions and it was hot outdoors. However, I was indoors most of the time.. The temperature on one trip was near 120Â° F and I was outdoors several hours and the low humidity made it tolerable so I don't see the temperature outdoors as a factor.