Why do you want the very hottest .357?
Can't answer for the OP, but when it comes to hiking the hotter the better (staying in spec). I hike in Wolf, black bear, Grizzly, and Cougar country on a regular basis. I normally don't recommend a 357, but my 44 is getting too heavy for me with with multiple injuries. I've just started packing a 357 and I prefer 158 grs. with 14.5 AA#9. This will float a 158 through the air about 1400-1450 fps from a 6" 357. I would love to go beyond, but that would take me out of SAAMI spec.
This is my hottest load. Although, I do have some 125s loaded to 1750 fps with 18.6 grns of AA#9. Still in spec with the Hornady reload manual.
One of the reasons I prefer this powder... I like Hornady bullets and in my 4th edition Hornady reload manual this powder is king.