So I took a look to see what I used -- it looks like 20 gauge magnet wire. It must have come with the kit since I have a coil of it in my bag of foreplay parts.
Unfortunately a lot of the solder joints look pretty bad so I'm going to undo most of it and start again. Probably best since I don't know where I left off.
I also have an Anticipation upgrade kit, and printouts on pseudo dual mono PS, filament snubber, multiple outputs, and single series shunt stepped attenuator, phew!