I have Coll de Dama Negra and Coll de Dama Blanca, and both are vigorous and healthy growers.
Very probably they are different strains from UCD Coll de Dama.
Coll de Damas are not the most productive varieties, but produce decent crops.
It seems to be a bit more productive CDD Blanca than CDD Negra.
Here a picture from http://www.galgoni.com showing an old CDD Blanca with a decent crop:

The main drawback for me is that they are late varieties.
I am hopeful with Coll de Dama Blanca&Negra, it is two week earlier, and for me it can be the difference between to get or not to get ripened figs.
At the moment, Coll de Dama Blanca&Negra is slow growing, but it is soon to get conclusions, it is an small plant yet.
it is worth trying, they are excellent taste varieties.