I'd say use whichever 300gr or heavier @ 1200+ is most accurate in your revolver. Corbons is good, Garrett makes a very powerful Ruger only 44 load but does have "light" (if you can call a 310gr @ 1300+ light) load for all 44 magnums.
http://www.garrettcartridges.com/products.asp
The Mountain gun will handle the loads fine, better than your hand will most likely.
The ability to handle the heavier loads was part of the endurance package that S&W built into their N frames in the late 80's.