H4350 is the most often recommended powder for the 300WSM on the 24hourcampfire realoading forum (I've surveyed all the 300WSM threads for the last 8 years - I am very anal). Second was IMR4350.
Based on my experience for 180 TTSXs (the only bullet I've focused on), H4350 was the most accurate AND most consistent of all the powders I've tried (i.e., IMR4350, VV-N550, VVN560, RL17, RL19, IMR4831). IMR4350 and IMR4831 also produced good groups (MOA or better).
H4350 is also the powder recommended by John Barsness for the 300WSM and 180 grainers(Barness, former editor of handloader magazine).
My 180 g TTSX pet load is 62.5 g of H4350 (2945 fps). For the 168 TTSX, it is 65 g of H4350 (3050 fps). However, I've not tested other powders for the 168 TTSX - that will change after this summer.