Wow! That looks great!
I think it looks at least as good as this one:
http://radioatticarchives.com/radio.php?radio=7894
I couldn't find a schematic for your set. Looking at other Westinghouse sets from around that period they used a 3.2 ohm voice coil impedance. I think a choke that could be used to substitute for the field coil is a 5H 50ma Hammond choke carried by tubes and more. Their catalog number is P-T155H. It should provide adequate filtering and has a similar resistance.
This is only an educated guess so don't hold me responsible.
If you look at the photos in radioatticarchives you can see that they replaced their speaker also with a permanent magnet one. It appears that they kept the field coil and hid it under the top. You can see the wires going from the plug up to it.
Another worry is weather the audio transformer was mounted on the speaker or if it's in the chassis. Hopefully it's in the chassis or you have to add one.
John