Remember that WST is reverse temperature sensitive. Hot weather will decrease the pressure and cold weather will increase it. In 2013, when I resumed reloading again after a ten year hiatus, WST was the only powder I was able to find. My load of 4.7 grains of WST behind a 124 grain plated bullet functioned fine in cooler weather, but in the summer it would eject weakly from my SIG P228 and Glock 17. Bwxmas is correct about WST being clean burning.
Different powders are more available now in my area so I bought BE-86 for my semiauto pistols and am using the WST strictly for .38 special and 44 magnum reduced loads.