WNY,
Congratulations on your new toy. It'll serve you very well for hunting, plinking, and, if you're like me, just holding, and admiring it. LOL!
You're on the right track with your bullet selection. The 158g SP's( I prefer Remingtons) are hands down the best over all choice for deer in the 357 magnum. I've killed a butt load of deer with a 357 rifle, and 11 with my 357 Blackhawk. I've tried literally dozens of load combo's ranging from 125g to 180g, and the 158g SP's either slightly edge out the others, or just plain out stomp'em as far as terminal performance. It's common for the Remington 158g SP's to bust a facing shoulder, tear the vitals up very nicely, then bust the off side shoulder, and exit. I've done it a bunch of times with them even at impact velocities in the 1700fps range which can tear other bullet designs apart to the point of never reaching the vitals. The beauty of it is that they also work very well at normal revolver velocities too.
If you haven't tried it yet, I highly recommend that you push that bullet with a full house charge of Lil' Gun. It pretty much stands alone in extreme velocity performance in the 357 magnum in either a revolver, or a rifle.
Good luck, and happy hunting!