I've got several trilite lamps and I got tried of throwing away expensive half dead or rather third or 2/3 thirds dead tri-lite bulbs.
I wanted a dimming feature so I soldered a standard 1n4007 diode across the two contacts at the bottom of socket, Use regular bulb up to 100 W and I now have> off, half wave, full AC,full AC off . etc
Great dimming feature and no flicker, seems the persistence in the filament holds brightness level and da wife doesn't complain or even know for that matter, so passes usability test.
Not sure how Non north american tri lights work or even if they exist or if half waving 50 Hz will be noticeable, but mine have been in use for many, many years and bulbs never get changed as it is dim mode most of the time except when turning off. One is on a wall switch outlet, so it hardly ever gets a full blast
cheers