I've looked at Stb_Yaw_P and have changed it from 4.5 to 3 but am not sure if I'm changing the right parameter for what I want. I want to just slow down yaw for slow panning when I film. At 3.0 it's not slow enough so I'm wondering if this parameter just gives more power to the stabilizer to hold the yaw based on the magneto.
Yaw axis stabilize (i.e. angle) controller P gain. Converts the error between the desired yaw angle and actual angle to a desired yaw rate
Just after posting this, it looks like I found my answer :)
So I need to change ACRO_YAW_P