Salt Water Caps

I have completely finished my coil except for the capacitor.  I'm 
planning to build some rolled polyethylene caps as soon as I gather the 
required materials and find the time.  Until then, I would like to easily 
construct a salt-water capacitor so I can play with the coil until I 
build a better unit.  I was not really able to find anything online about 
salt-water caps, but I keep seeing references to them.  What would be 
required to build one capable of withstanding a 15 kv, 60 ma neon 
system?  The secondary is 24 inches, 6 inches diameter, 880 turns 22 awg 
magnet wire.  Primary is 14 turns, conical spiral, 1/4 inch copper 
tubing.  Spark gap is a 6 inch, 16 electrode disk rotary system.  Any 
advice would be greatly appreciated!