Tesla Coil Revisions!

	Hey again.  Well, my coil is sitting in my garage, anxiously waiting to
get worked on some more.  As I posted earlier, I blew my 12Kv/30mA NST, and
it was indeed a destroyed secondary, not just carbon tracks, so I junked
it. But, I have recently come across a goldmine of neon transformers. :-) 
Now I have six 15Kv/30mA units, and I can go back and get more if I have
such a desire. :)  Anyway, I am going to give the new specifications of my
coil.   Please look over them and notify me of any flaws.  Also, give me a
prediction on what the spark length should be when I get the system finely
tuned.   Thanks a bunch.

Secondary:  4" PVC with a 22" winding of #26 AWG magnet wire.
    Primary:  .25" copper tubing in a flat spiral.  Spaced a little over an
inch away from the secondary, and each winding is half an inch
                  apart.  15 turns total.  
       Torus:  Aluminum pie pans and dryer vent duct. :)  About 17.5" x 4".
Capacitors:  A multi-mini system.  It's .007uf.  I made it for my old
12/30.  The right capacitance for a 15/30 is about .005, right?  I will    
                   get on building a new cap soon.
Spark Gap:  This is tough.  I want to try building an "air-blast gap",
because I found a very high-power fan while browsing the junk yard.
                   Please, feel free to offer sugggestions! :)
      Power:  15kv/30ma NST.