Well, after alot of scrounging, work, arc drawing and very little spending, my 4 MOT stack is somewhat somplete. All it awaits now is being submerged in oil to help with cooling. So far I have spend about $40 Canadian to get it to where it is. Maybe another $30 will get it to not overheat by filling the container with oil and replacing the two smaller MOTs on the left with much bigger ones like those on the right. So far I've found two extra large MOTs with 14AWG for the primaries, compared to the 18 or even 20 gauge I've seen on most MOTs. These heat up a lot less than the other two MOTs and their 18 AWG primaries. After they are in oil I should be able to run at 10kW for long peroids of time, until the oil heats up enough to cause concern, such as the container sagging from the heat and making a mess.
The 4 pack currently puts out about 12kV at 700 to 800mA (not yet measured), and draws alot of current because I need to add a bunch of power factor correction. Currently running at 240V in, maybe 50 or 60 amps. I should be able to cut this down to 40A at full power, and less if I add more MO caps in series with the HV end to limit current even more. The eventual goal is to lower input current to 30A.
Below is a picture of one of the arcs drawn from it. The nail in the lower left is 6 inches long. That picture was taken during 120V operation, the arcs now are even bigger.