I use WC-860 and WC-872 with my Krag and NOE 311-202-RN (~210 grains)…

I am shooting them from an MGM custom 26” barrel on the Encore frame…

Not quite the stuff you guys shoot, but still a 30-40 Krag!!!

Anyhow, 49 grains of 860 with the NOE boolit are giving me ~1979 fps (chronographed)…

And 49 grains of 872 with the NOE boolit are giving me ~1974 fps in a Graf case and only 1854 fps in a Remington case.  (chronographed)…

Not sure what velocity you might get from a 150 grainer.  It’s likely it could be a bit less than the 210 I am shooting as the 150 might not give enough pressure to allow the super slow burners to really get going.  I guess only a chronograph could tell that tale…

Good-luck…BCB