Some of the Great War Minis packs work well for Freikorps because they have light kit. Typically, the Sparatacists and other Reds didn't like to wear the Stahlhelm because they associated it with the Imperial Army. Ex-army Reds usually wore the cap with visor (with the cockades taken off) and sometimes the round pillbox type cap (Mutze). Freikorps often wore the Stahlhelm, but there are plenty of pictures of them in the visored cap too (and I have seen one picture of ex-Garde Jagers wearing the Jager shako for a parade in Berlin - but with every issue jacket imaginable, including both the Bluse and the 1914 issue).