Run away!
Picture courtesy of Derek Woodroffe http://www.roffesoft.com/tesla/derby2005/index.htm
On the way down to Derby I stopped off at CCL Veloduct and bought two lengths of 8" diameter flex duct. Next stop was the local Metal Supermarket for three 1-metre long aluminium poles.
At Derby, we assembled it into a giant 8" x 48" ducting toroid which was placed on the OLTC2. (thanks to Finn Hammer and Phil Parry for practically building the whole toroid for me) After a lot of fiddling (and getting the quench settings wrong which Derek finally spotted) it came into tune with about 32uF of tank capacitance, started sucking over 4kW from the wall, and bolts began to rain down from on high!
The longest arc we got was 81" to a grounded target. There were also flashovers down the length of the secondary, and strikes to the floor. It finally struck the cables leading from the power supply to the coil and blew something in the driver box. It was near the end of the day so we just left it.
The OLTC2 has now (barely) out-sparked Dan McCauley's DRSSTC to become the world's third most powerful solid-state coil. I won't be trying to get any more out of it- it'll be easier to just build a big DRSSTC.
It has also got me into an elite club of HV enthusiasts who have sparked more than their own height ;)