RE: better deer bullet?
IMO, those choices are leaning towards the light side if your interest is long range trajectory, and of course you'll want to hold energy upat distance as well.
Assuming you're referring to .50cal sabot & .45cal bullets...one of the best sabot/bullet combinations I've ever used was a Hornady .452/300grn XTP...took several deer with it in an MK-85...dropped the biggest mature 8 pointer of my life in his tracks at 165yds.
Weight is actually a plus when it comes to holding up trajectory and energy at distance...light bullets slow down too quickly...my advice would to to think in term of at least 275grns...300grns is better