This is very interesting. I bought my Foma 100 classic from Retro Photographic here in the U.K. According to their latest advert in Black & White photography magazine, they now import Calbe R09 and recommend it for traditional high silver content emulsions like Efke and Foma because it follows the pre-war formulation of what is now Agfa Rodinal.
I'll try half of my roll of Foma in Calbe R09 as this has to be a good starting point, and develop the other half for comparison in ID11 1+1. Alan Clark