[Arran]

Terry;
  That sounds like a logical course of action, especially with a dirty set, I will have to do something similar with a 10'' Magnavox speaker, in a Deforest Crosley, at some point, judging by the thick dust that was all over the chassis. I've often wondered how they centered the cone in a speaker with a solid spider, considering that you can use shims, it must have been by ear.
 I don't have a Philco with a pie pan, but I had to repair the speaker in a 620B, an 8'' one, where someone had reconed it with a more modern foam rimmed cone, and not very well. The spider was a 45 rpm adapter style, and was trashed, so I made a new one out of stiff card stock, and a razor knife, I used old film negative for shims, cut into strips, though the plastic from blister packs would also work. I also used contact cement to glue the spider in place, and painted the foam with it as well, just to preserve it, seems to have held up though I haven't inspected it lately. So if anyone wants to replace the solid spider in a pie pan speaker a stiff cardboard, or plastic, of the right thickness can be used to make a replacement.
Regards
Arran