[Arran]

I will have to find that roll, which I got from a NAPA dealer years ago. It's not like the normal gasket paper in that it's the variety which would resist gasoline, or other fuels, for use in carburetor and fuel pump gaskets, which is what I used it for. it looks almost identical to fish paper, so I doubt whether ordinary moisture would be a problem. The reason I ask is that I took apart some IF cans in a Stewart Warner vibrator radio, and they had a cloth with a sticky varnish type substance on it rather then the typical fish paper, or varnished paper like your Philco had, and it made it difficult to get the covers off of the IF cans. Needless to say I removed them to get them back together, as I did not unmount the cans from the chassis. I'm curious about the electrical specs, if it has any at all, it's not a problem getting something else but I have basically a lifetime supply of the stuff. I may have to make a test rig, another trick to limit current is to connect a light bulb in series with the primary, though that will reduce the output voltage under load.
The B+ in the Stewart Warner is only about 180 volts as they used battery tubes rather then AC tubes like a Philco or Brand Z set would use. It was in a similar condition to your poor 46-480 rust wise, but the reason I started fixing it is that you could power one of these sets from a single 6 volt SLA battery so they are almost practical to use as a modern solid state radio. I also felt sorry for it, it was literally sitting on a junk pile, but it was also almost complete, only missing a single knob.
Regards
Arran