Actually I'm not even concerned with productivity as much as I am trying to figure out how to hang on to the hygienic traits. My first package ever was Midnights from Weaver, so I understand about always having to go back to the breeder for queens. I was just hoping this time around to be able to breed a few of my own without loosing the hygienic traits I am so interested in encouraging. Sometimes it is a real hassle to have to send for a queen. What I'd like to do is breed a few and have a nuc or 2 on hand for emergencies.
Very difficult / impossible to get a true purebred. For you, just go with bees you like, whatever they might be called. You'll be looking for gentleness and productivity. Keep it simple.