Don Teach emailed me to say that Ragland Piano Company in Texarkana,
Texas, has lower valve seats for Wurlitzer valve blocks.  I looked
at their website at https://raglandpiano.com/ and then followed its
link to Ragland Piano's eBay Store at
http://www.ebaystores.com/raglandpianocompany 

And wow, do they ever have parts!  Sixteen pages of parts, with
pictures.  Kinda reminds me of Durrell Armstrong's long-gone Player
Piano Company, which I miss very much.

Matthew Caulfield
Irondequoit, New York