Quoted from RobertWinter:
3kv seems rather small, even though KingBW has that on his sign. You would need a minimum 6kv transformer for 10 feet of 10mm tube (assuming that's the size of your sign). 7.5kv would give you some headroom.
Since you already have multiple transformers, I would suggest splitting the sign.
This weekend, I was thinking of separating the ghosts from the pacman words and trying something like that with 2 transformers. I may also go back and try cleaning off the leads coming out of tube as the copper seemed a little dark like a little oxidation (or maybe from heat). Thinking a lite fiberglass brush or something gently.
Thanks for the extra input.