Normally I only use titegroup for loading my 148 gr. wadcutters.

For my 158gr 38 special I like using Power Pistol. In fact my favorite 38 special load that I make is:

158gr hornady LRN or SWC-HP
4.9gr Power Pistol
COL 1.455"

For 357 magnum I like using Hornady's 158gr XTP's & 13.9gr H110 @col 1.575"