"366 and change"... dang, nice!
I've had six 300 WSM's... after farting around with every powder that seemed adequate to the cartridge, I settled on H4350. That doesn't mean I won't play with other powders (I'm going to give H4831 and RL17 a thorough workout in my current Kimber MT), but H4350 has given consistent and predictable results... 2,950 (give or take) with 180's and 3,050 with 165's.
I've taken four elk and a few mule deer and antelope with the round... I like it best as an elk round, but it sure works on everything!
Cartridges are more alike than different.