Your plan sounds fine for the supply. Neon high tension cable is fine and the tygon tubing is a fine sleeving for the feedthru insulation.
For a demo fusor supply I would use the system as a full wave, grounded center tap system. This would give an output voltage, unloaded of just over 10KV. I think I actually published this diagram in the ESJ article as well as Volume #6 3and4 of the Bell jar. The article is online at Steve Hansen's bell jar site.
Richard Hull
Created on Thursday, April 12, 2001 12:40 AM EDT by Richard Hull