With 158g bullets I think you will find blue dot and aa9 will work well at the velocity you are seeking. Blue dot at about 1 to 1 and a half grains under max has been the most accurate powder for 158g bullets in my 6 inch barreled 357 revolvers
In the past, 12.1-12.3 gr. of 2400 has done well with 158 gr. SWC with my revolvers. Quite the manageable magnum (lite) round. I tried them out in the rifle. I got lube fouling after shooting about a 10 rds. I'm going to kick it up a grain or two and see if that will be better.
Magnum primers are for use with harder to ignite ball powders and in loads that will be shot in extremely cold weather. Flake powders ignite easily and standard primers are all that is needed. The extra burn of the magnum primer produce higher pressure at lower load levels with powders like 2400 that can result in over pressure loads with the substitution of the mag primer. Read the current Speer manuals that warn not to use magnum primers with 2400 loads in their manual for .357 magnum.