"Koz" wrote:
We usually guessed at the old standard of 10000 v per inch. However,
I've since heard that even though this used to be common, it barely even
qualifies as a wild-ass guess.

Yep. The reason being that multiple streamers are occuring in succession
and following the previous spark at hundreds of times per second. One
streamer ionizes the air making it easier for the next streamer to follow,
until you have the big long streamer (all of this in a fraction of a
second). This can be demonstrated by running a TC in single shot mode and
noticing the significantly decreased length in output.

Jon