Primary Spacing Toroid size??

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "raven0075 by way of Terry Fritz <twftesla-at-uswest-dot-net>" <raven0075-at-home-dot-com>

Distance from primary to secondary in a pancake spiral, what is the normal
recommended clearance? I made mine 1 1/2", seamed to work ok.
And if you space the primary between spirals at 1/4 inch verses 1" what are you
going to see in performance?
 
According to Tesla Coil construction guide, it says a toroid should be 40%
larger than the secondary diameter, well I tried that and then made a toroid
70% larger and had way better results. 
 
I have seen several toroid designs, shoud you make it flat on the bottom mount
or does this really mater.
What works the best?
 
  ____
(_____)  
     I I
Thanks
Brian