Help designing 18 inch coil

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

Original poster: "Peter Terren by way of Terry Fritz <teslalist-at-qwest-dot-net>" <pterren-at-iinet-dot-net.au>

Hi all
I am going ahead with an 18 inch coil and have had a very nice 18 x 59 inch 
former made up from polypropylene. I am a bit undecided about construction 
of the secondary.  I have a feeling that 54 inches of 21 G at 1680 turns 
would be reasonable as I have a preference for a high inductance, large 
toroid system as this seemed to be good for my 6 inch coil with sparks of 
96 inches = 3 times the secondary length of 32 inches. I also have a 
preference for a large diameter primary possibly even with fairly high (but 
more even coupling) as per Richard Hull's Nemesis. 
<http://www.richmond.infi-dot-net/%7Erhull/highenergy004.htm>http://www.richmond.infi-dot-net/%7Erhull/highenergy004.htm

What would other people do (and more importantly, why)?

Details on 
<http://members.iinet-dot-net.au/~pterren/feedback11.htm>http://members.iinet-dot-net.au/~pterren/feedback11.htm

Cheers
Peter (Tesla Downunder)