The "Cold-Cathode" systems I worked on had a Transformer with Secondary output of 120ma @ 5KV (600 VA), with a 120VAC Primary.
Heavy sucker!
One was sent with a broken Bushing (Insulator), and the replacement took weeeeeeeeeeekkkkkkkssssss to arrive!
Funny thing about the Cold-Cathode Transformer, it had no Secondary GFPE included!
The "Normal" Neon setups I have seen in the last couple years, used Transformers with GFPE sensing for the Secondary + Lamp circuitry.
All setups mentioned here used GTO-15 cable.
Scott35