When a manufacturer does not list certain of his powders for certain loads, I pick another powder.
Since the "speed" of a powder depends on how it is measured, you really have no idea of the relative speed of WST in a pistol loading relative to another powder.
Trying to guess loads based on rough guides of powder relative burning rate is extremely poor reloading practice, and a good way to blow up a gun. There are many proven loads for 147gr 9mm in the loading manuals. WSF and longshot, for example.
http://data.hodgdon.com/cartridge_load.asp