I opted for a scratch built TC. Except for the following modifications, the design was nearly identical to the monopolar version that I described in a previously published i'ble (https://www.instructables.com/id/Tesla-Night-Light/).
I mounted the secondary horizontally, disconnected it from ground and then capped the ends with aluminum discharge globes bolted to ceramic insulators. Lastly, I used a concentrically coupled coil to replace the pancake primary. Once the TC was completed, the remaining construction was intuitive.