My head is now spinning
Didn't you say yours was a quarter plate?
Mine is a 3 1/2 by 2 1/2. That might explain some of the differences. That also means neither 'special' nor 'Junior' refers to the plate size. I'm beginning to think they just strung as many brand names together as they owned the rights to and stuck them on the name plate...
My camera came with a really nice Taylor Hobson Cooke Anastigmat 5" lens, which is not in a sunken panel. I've also got a Carl Zeiss Jena 15cm Tessar which is a nice fit.