Main spark gap across one or both transformer legs?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: John <guipenguin@xxxxxxxxx>

Hello, I have two questions. I am in the middle of gathering 
materials and designing my first coil SGTC.

What is a better design....having the main spark gap across the two 
transformer's legs...and have the cap bang on 1 leg...or have the 
spark gap connect across 1 leg and have the cap bank connect across 
the 2 legs of the transformer?

Also, if I plan on using a transformer around ~9kv 30mA   is it 
completely necessary to have a full protection filter such as 
<http://www.classictesla.com/download/NST_Filter.jpg>http://www.classictesla.com/download/NST_Filter.jpg 

or can I just make two chokes, wrapping wire around an extremely 
small diameter PVC pipe along with a safety gap?

Thanks.