Gold equivalence of blood slaves

[JimMorrison]

What about if you have a Dousing bonus from your pretender, specifically the +15 from Fountain of Blood?

But also, most B1 mages are not old age, so capping their life expectancy isn't really necessary, is it? Many B2 mages are old age, but what is the difference in hunting efficiency with B2+rod vs B1+rod?

And also, while some nations do get extremely cheap B1 mages, what about nations like Pangaea, who only get very expensive blood mages?