There are papers online that discuss the need for persistent capri to make persistent new wood females (main crop). Persistence on old wood (breba crop), however, isn't mentioned much, if at all. I don't think breba persistence is well understood yet. Not from what I've read anyway. Just from my limited observation, breba and main persistence seem to operate independently of each other, suggesting different genes controlling this. I'm not sure how breba persistence is passed on.
Just a thought, but you could try crossing Desert King, which is known for having a great breba crop, with a persistent capri to maybe get something that makes two full crops. It's worth a try anyway. I have 11 months of heat here, so I know that cross is in my future plans. Good luck.