I would advise going labour and adopting WTB plan, and supporting it at every rally. Don't forget to get the Reichsbanner and the Prussian police to work together to be able to have rallies undisturbed by the SS, and make sure to have decent amounts of public support from the radio system. Btw, you can have the civil war event but not really have a civil war if your have a large enough military presence, causing the Nazis to retreat early (I'm not sure if that works here, but it works for sure on redux).