Is transformer output impedance important?

["Seth Fischer" <aureo@xtra.co.nz> (by way of Terry Fritz <twftesla@uswest.net>)]

I am a first time coil builder and am basing my coil on the Information
Unlimited design published in the July 2000 issue of Poptronics.

But I need some help with changes I will be making:

Instead of the specified 4x4kV 30mA  transformers (series/parallel to
give 8kV 60mA) I want to use neon sign transformers and a variac.

Will I need to change the pri/sec design?

And, why is the neutral conductor bonded to earth? I thought this was a
big no no with the Multiple Earthed Neutral system.


Thanks
Seth Fischer