Me next to my coil to give an idea
of scale

Secondary Coil Design

Diameter of secondary coil : 200.00mm
Winding height of secondary coil : 600.00mm
Wire diameter for secondary coil : 0.72mm
Spacing between windings : 0.00mm
Secondary turns : 833.00
Secondary wire length : 523.39m
Secondary inductance : 39.59mH
Approximate resonant frequency : 223.20kHz
Secondary quarter wavelength resonant frequency : 143.30kHz
Secondary self capacitance : 12.84pF
Toroid capacitance required to form quarter wavelength coil : 18.31pF 

Primary Winding Design

Primary capacitance : 0.0127uF
Primary resonant frequency : 143.30kHz
Secondary coil diameter : 200.00mm
Primary conductor diameter : 9.50mm
Primary turn to turn spacing : 9.50mm
Spacing between the secondary and the inside turn of the primary : 62.50mm
The primary will need to be tapped between turn 12 and turn 13 to form a resonant circuit at 143.3kHz

The approximate inductance at each turn is :
Turn 1 0.76uH
Turn 2 2.85uH
Turn 3 6.11uH
Turn 4 10.51uH
Turn 5 16.06uH
Turn 6 22.79uH
Turn 7 30.77uH
Turn 8 40.05uH
Turn 9 50.69uH
Turn 10 62.76uH
Turn 11 76.33uH
Turn 12 91.46uH
Turn 13 108.24uH
Turn 14 126.73uH
Turn 15 147.00uH

Neon Transformer / Primary Capacitor Matching

Transformer secondary voltage : 15kV
Transformer secondary current : 60mA
Number of transformers : 1
Primary capacitor required to form a resonant circuit at 50Hz with neon transformer(s) : 0.0127uF

Air Blast Gap

Primary Tap Clips