Well - I decided to get at least one weekend of flying in on this plane before sending in the ignition for the upgrades. I added a hose clamp to secure the braid to the plug base as recommended.

Took the plane to the field. Fueled up. Flipped and flipped and flipped and flipped...

Pulled the plug and found no spark.

We adjusted down the gap between the magnet and the hall sensor. Got a mild shock when we switched the ignition on again - I don't know if the ignition fired or if it was just a random pulse of current.

Still no spark.

I'm not sure whether I accidentally blew the ignition or Hall sensor at some point... I've another engine which uses the same ignition module (a TS-52), so I'm going to rob it and see if the BME starts making noise