Fitted much pet tolerant stuff over the years and the only PIR's I am confident in are the Bosch one's above.
If using anything else I would use perimeter protection.
Double knock is not an appropriate method of reducing false alarms, full stop.
I never give a guarantee that a 'pet immune' system will work.
The only guaranteed way to make an intruder alarm work is to keep moving objects away from sensors that detect moving objects!.
Place animals in an area that isn't covered by a pir, it's not rocket science tbh.