Neon Transformers High(er) current?

I'm going to be powering my coil with one or more neon sign transformers,
and I wanted to get some info on what I should obtain when I am ready to
go to more power.
I currently have a 12kv 30ma unit, should I obtain more of these and run
them in parallel, or should I replace them with higher current versions?
Or, should I just try to always get 12kv units of whatever current rating
is available and parallel them up?
When paralleling transformers like this, should I be attempting to match
actually output voltages to within a certain tolarance, or will it make much
What about protecting my neon power supply?  I'm sure this subject
has been beaten to death here, so could someone refer me to a good
URL on neon protection?  I've heard that some people only use a saftey
gap, while other people use handmade RF chokes.  I read once that
most handmade FR chokes were mostly ineffective (sorry, no refrence
on this), is this really a problem?