Ground Rods & Secondary Leads: How long is too long??

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

Original poster: "Ken Stevens by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bluewaterdiver-at-earthlink-dot-net>

What is a respectable length for a ground lead off the secondary coil?

What is too long? What's the max I could expect to make it and not
suffer decreased performance? I planned to go from 22ga magnet wire to
some glass/ptfe coated 12ga nickel plate stranded probably shielded in
1/8 wall silicone tubing. Excessive, but it'll never go bad!!!

What's the shortest rod I can get away with? I have fairly damp soil, so
I wouldn't think I'd have to go too horribly deep. I've watched the list
and somewhere between 3-5' seems to be the norm, but I also saw the
posts about the dog leash screw which would seem plausible in really
moist soil!

I can drive a grounding rod into several places, but I only want to
drive in one, so I'd like to make it as central as possible to all spots
I intend to run. If a really short screw-type thing would work, then my
only real concern is actual distance from the "ground".

Thanks,

Ken