Time and patience to set up and test. If you have concerns about losing your current setting back them up on camera and BI, so that you can restore them later if needed.
I'm not using any scripts to use IVS in BI for my PTZ.
I have a 5231R-Z12 that works really well using only BI for Motion/object detection.It's as good if not better than using IVS.
I will try to setup the z12 & IVS in BI later today and post some configurations & instructions.