The Lamp Room

I might try a few different tubes on single proper 2ft 40w gear to get some average amps/volts readings then rig a pair up as you say and compare the results.

Ash it would be nice if you could make some

Tridonic used to make merc ballasts in fluorescent choke form for use in bollards etc. I have one in 50w. Can’t remember the code but I’ve seen them in 80w as well so one of them would be ideal. It’ll fit in a modern 2ft twin fitting.

I will be able to when i get things going

Just converted the 2' 40w batten in the test rig in my workshop from 2x 20w ballasts in parallel to the proper Tridonic ballast for a single 2' 40w tube

Good good. Finally the ballast gets a use. It was just sitting in a storage box so glad it’s now been put to use. They big old lumps aren’t they. Same size as a 8ft choke lol.