Extreme High Voltage: TinselKoil 8: Bipolar Slayer Success !
Using the 2sc2238a transistor and no connection from Base to the secondary, just pickup, I managed to get the TKoil8 working in Bipolar mode.
After I made this video I discovered that sticking the Base trigger pickup wire _into_ the secondary at the right-hand end works even better; now I can light up all 10 neons brightly.
Thanks Terry Woodroof for the examples and inspiration!