Ed Sonderman's mini coil:

NST: Franceformer 4kV/20mA, 5 shunts removed top and bottom.  Measured Isc current  46 mA. 4,000 v x 46 mA = 184 VA

NST primary operating voltage = 118VAC.

Tank capacitor:  Two Maxwell .035 ufd caps in series for a total of .01528 ufd.

Primary: 13 turns of # 10 bare copper wire. Inside diameter 5.8". Spacing  between turns .35". Tapped at turn # 6.7. Flat spiral.

Secondary:  Three inch diameter acrylic form wound with #28 wire for 13.1" winding length

Spark gap: Two 1.5" dia. x 4" long copper pipe sections mounted .050" apart.  Small microwave oven fan for cooling.

Top load: Two toroids - 1" x 9" mounted on top of secondary, 1" x 11" mounted on top of that with 2" metal spacer between them.

Max spark length 10.75" using a breakout wire on toroid, discharging to a grounded wire. Location is Spokane, WA, elevation 2400 feet.  Elevation derating factor has not yet been applied or determined.