Bill, for what it's worth my 12" Dagor was sold for next to nothing with a 10x8 Agfa Ansco Commercial I bought from the US (off a Professor of Photography, this second owner said it was too old a lens and never used it. Instead he used a Nikon M 300mm, he old the lens board for it along withh some blanks and an UNUSED Beattie screen. I have an M 300mm but prefer the dagor.
THe original owner had studied and later taught at the Clarence White Shool of Photography and only bought the very best, and 1940/41 that was a Dagor and an Agfa Ansco. I had brief contact with him shortly before his death.
When I first tried my 12" Dagor I had no expectations - well in truth I expect it to be flaky, instead I found something that could match modern lenses with no diffioculty. Your lens should be even better.
I wouldn't sell my 12" Dagor I'd sell mmy Nikon M 300mm first, but we all have different agendas. I keep 35mm gear yet have very rarely used it in over a decade, possibly longer.