At its outset, you short put is basically completely "financing" the cost of your long put (but for the $3 it cost to put the trade on). Your goal is to roll the short option forward for duration, collecting credits along the way and to exit the setup for a debit that is less than what you collected in credits (as you would do with any credit spread).
Unfortunately, the metrics of such a setup are indeterminable, although it does cost about $350 in BP to put on. A number of things can potentially happen during the life of the setup, and the credits received for any roll of the short put are unknown.
Basically, however, I'm going to work the short put as I would a naked, but with the benefits of the long option keeping the risk defined ... .