In my opinion, the 154 would do you fine for "everything". However, the facts of the matter are that you will be hunting deer, so develop a deer load. Start with the 154, and if that won't shoot, try another in that weight class.
There is very (VERY) little difference in drop between the 154 and the 139 at ranges where drop becomes relevant, and that "disadvantage" is compensated by the fact that the 154 will drift less in the wind. I've been told the wind sometimes blows a little in S.D.?
If you go to
www.huntingnut.com, you can download the Pointblank exterior ballistics program for free. Play with it, and you will find that the benefits of using lighter bullets are small, and there are some pretty substantial penalties (the wind drift I mentioned, as well as lower down range energy. HTH, Dutch.