Just my 2¢
I have never had success with 29 or H110 in the .357, although it is my powder of choice with the .44 Mag.
I have loaded over 100 different loads in the .357 in the last 35 years, and by different I mean the gamut.....296, H110, 2400, Unique, AA9, AA7, AA5, 7625, and more....
The winner by clear margin is 2400 in 4 different guns from a RM to a PC gun with 5" barrel.
14-14.5gr. 2400, Federal small pistol magnum primer, 124jhp up to 160gr Keith bullet with gas check. Accuracy is incredible.
Here's the thing. If you use a proper GasCheck (GC), the cast hardness is not nearly as important as would be if shot without GC. I use BN 15 for mine, and find no leading. I love the Keith bullet with 14gr. try it.