[Radioroslyn]

Hi
The bottom line is if you want to you can use the original speaker for it's FC and output transformer. Leave it connected as is. Find a suitable modern speaker that fit where the original one came from.Disconnect the two wires that go from the output transformer to the VC. Connect two new wires from the output transformer to the terminals on the replacement speaker. Leave old speaker in the cabinet
A few notes. Philco used odd size speakers. Most common replacement that will be close to the size you need is 8". ( I think your set uses the same size for the table and the console models) Philco used a 7 1/2" or so one. So you may need to do a little work to fit/mount the 8" job in there. Truth be told size doesn't matter so much but the impedance does.
The Philco speaker VC impedance is about 1 1/2 ohms. Modern standard speakers are either 4, 8, and 16 ohm. what you are looking for is the 4 ohm. It's the closest you can get and will work fine. This is the answer to your original question.
Hope all this helps
Terry
ps Don't know where you are located but if you near eastern PA big radio convention here Fri and Sat.