neon sign transformer confusion

[forest]

IMHO You can use any parts , it doesn't matter, just take whatever you have with kV range. The essence is you have to measure LC resonant frequency and the length of secondary to be 4 times the primary. Here is the catch I think.
The secondary is like a mirror of primary with diodes used to pump capacitor.
The first thing I would check is the method used on primary side. It is weak method to charge capacitor with impulses - I would try if it works in such configuration, the performance doesn't mattter. It's usd to pump LC circuit at correct frequency and the spark is the limit. IMHO it may waork in two different modes, I don't know which ose was used by Don. First is continous oscillations on primary are used to pump secondary resonance, the second is discontinous - the pumping is only strong when the spark gap fire. Weird circuit indeed, but the ideas are more clear now when you realize it has two resonances matched.

[Zeitmaschine]

Radioionic Energy Receiver

That schematic looks strangely similar to the Don Smith device arrangement.

Although I don't think it is the best idea to have an antenna stretched across the room connected to 20.000 volts. (C1 is rated 1nF/20kV)

[Tesluh]

has anyone built the above device, would love to see one. 

Can anyone speculate what the lug on the nst is connected to?  would it have to be a center tap or not necessarily.  Still having a hard time finding an nst that satisfies the needs of this circuit.  I did however get one in that showed a nice rising trumpet waveform right out of the box.  I think I ruined it though by using the "ground" wire.  it stopped giving me a nice trumpet waveform after I touched the ground wire to the spark gap.  I also should have recorded how I had it wired up because I am trying so many different configurations and now I cant get it to repeat.   

[Zeitmaschine]

would love to see one. 

Radioionic Energy Receiver

Don't know if mass production is already on its way.

[Tesluh]

very interesting, nicely built. 
As far as my nst searching goes, I found a similar nst to the one shown in the video you posted.  coolneon ng.a108ft  however the ground lug had a gfci attached.  since I ruined it anyway I decided to saw it apart (the resin was rock hard) and see if I could find a way to destroy the gfci without ruining the whole thing.  I was able to get at the center tap wires (I expected it to be impossible) so if I really want I should be able to "make" an 8kv  HF center tap non gfci with built in dimmer.  I am waiting on another one to arrive (the nice thing is they are only $37 ea).  hopefully I can modify it and make the circuit the way I think it should go.  http://www.ebay.com/itm/111994079297?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT