With the 140* loin you should have nice tender sliced pork, I would think wrapping it and taking it to 190* will leave you with either dry pork or something resembling pullled pork.
I had my wife's uncle bring me some "pork" to smoke for pulled pork. Turns out it was those pre-marinated pork loins. So I did, and it did fall apart eventually, and it definitely wasn't the best pulled pork I've ever had.
#1. I'd cook them both to 140* (because that's what I prefer) and I would also cook it hotter around 275* and hope for 2 hrs.
#2. If you decide to do one each way, for me I would cook the one fat end to 140* because I could keep the doneness more uniform.
Sorry if that's not super helpful, hopefully someone with more experience cooking loin to 190* will come along shortly. Who knows, it may be awesome and I just farked it up. Good luck either way.