Your boundary should be no R discussions. If she brings it up and wants to chit chat about things, then validate and actively listen. Pulling away and doing your own thing with a positive attitude is what you need to do. Don't be cold or mean or rude. If she engages, then engage and follow the validation path.
Another boundary should be that you shouldn't take disrespect and yelling etc from her. If she is mad at you, then calmly state that you're willing to have the conversation but not while emotions are running high, and you'll disengage if she continues this. And if she does, just politely end the convo and walk away. That's showing balls too.
So figure out what your boundaries first are. What are you willing to accept and what is outside of that. The boundaries are not about teaching her a lesson etc, they are to protect you and what is important to you.
Having gone through this, I know this dance is difficult and sometimes feels contradictory. Also don't over analyze every single interaction. If you think something went poorly, make a mental note to do it differently. One bad interaction isn't going to sink the ship.
Boundary setting should be done in general - even in healthy relationships. So doing it before BD is totally fine.
