@TooManyCats,

That username tho XD

I believe that the C420 has a few extra settings that can help, beyond setting maximum sensitivities:

Wake Up Sensitivity, this is above all the detections and should be maximized to increase the overall sensitivity

Correct Event Type - This option is available to detections that were recorded and will allow you to increase the accuracy of detections.

Clip Settings - If your cats are fast moving, your camera may see them and not be able to then create anothre recording, make sure you go into your clip settings and make sure that your settings are idea (30 sec clips, low retrigger time, and higher record buffer)

As this is a battery camera, the device does need to wake up before it starts recording, which is done using the cameras Infrared sensors. Depending on where your cats are in relation the camera, it's possible that the PIR sensor is not detecting them. Maybe try adjusting the camera to look more directly towards the paths you expect your cats to travel. (Technically, the PIR sensor will work best in left-right movements).

For this purpose you should be able to use the camera, however I would recommend considering a wired camera if possible. The advantage of a constant power source and 24/7 recording would make detections more accurate and a smoother overall experience.