The Fine Things are Always Hand Made
Be really tough to find that 2 pin plug. Suggest you make one.
Comparing a 6 pin tube (pre octal, era - like a 58) to the my Philly tweeter plug is about right.
The 6 pin tube has 2 fat pins and 4 thin pins. The Scott 2 pin plug has one fat and one thin pin.
Choose a dud or worn out tube. Separate the glass envelope from the tube base and unsolder the wires.
Keep one fat pin and the opposite thin pin and cut off the other 4 pins of the tube socket.
Assuming you have the Scott tweeters set of PM tweeters with the 2 mfd cap mounted on the one tweeter.
As for polarity, the Philly diagram suggests the fat pin is wired to the 2 MFD cap and other to thin pin/ground.
Thanks Dave for advice on how to proceed. Much appreciated.
If you intend to use an old tube base, after breaking out the old glass, soak the base in denatured alcohol for a few hours or overnight, this will soften and dissolve the old cement that held the glass bulb in situ,
leaving a nice clean socket.
I think that isopropanol will work but will take a little longer, the cement is shellac based with binders in, could be pumice, fine sand or anything they had back then.