IMR-4831 and H4831sc are what i use in my 280 with 140 gr BT & AB, RL-19 showed good results with a 160 gr Gameking, I'm gonna try H4831sc with that bullet too and see how it does.
I cannot offer any help specifically with the 150gn Partition. The 150gn Sierra Game King is flat out bang flop death to White tail, as the pictures show. The recovered bullet was on the backside left leg, between the rump and the hide. I was fairly confident I could make the shot since it grouped nicely from 400 yards, despite the fact that the day of the hunt the screaming wind at my back moved me a bit.
Loaded the 160 gr Partition for my fathers 280 Rem (7600 pump). The detachable magazine is the limiting factor for OAL, so IMR4350 got the nod for the sake of seating the bullet fairly deeply and not compressing the powder much. Superb elk round from that 22" bbl at 2820 fps.