I would start Taj Gibson over D.Jordan. He has much quicker feet and is the better defensive player against most starting PFs + he is a much better fit offensively alongside Cousins and your other starters.
Maybe I've played too much 2K, but I feel like I should give Jordan the start but give Gibson the minutes. I feel like Gibson's a great player, but I don't know how much more he has to grow which is why I think starting Jordan is so important. Am I wrong about that though?
I think DeAndre Jordan can continue to develop while coming off the bench. There are a lot of minutes available in that frontcourt.
You can give him 18-22 minutes a night as a center behind Cousins and another 10 minutes alongside Cousins -- a combination that would be particularly effective against teams with interior PFs or non-scoring PFs or most second unit PFs -- which would give DeAndre Jordan about 30 minutes a game to work with an develop with.
I don't he necessarily needs to start to develop. There are enough minutes available while coming off the bench.
Consequently, I would choose whoever you feel gives you your strongest starting lineup.