Hi,
Have you tried to run C.A.T on any Rasp Pi 3 yet?
No, I tried on an ASUS tinkerboard, but did not work with the early OS.
No, neither a Rasperry or a Tinkerboard would be a choice anymore for me. The idea was to use my mobile phone, notebook ... on the go, as well to turn off my desktop if not needed anymore. Just to for running C.A.T. to turn on a desktop is overkill. Raspberry would be fine, but again speed, and access from my mobile phone would be a problem. The Digital Ocean droplet I suggest in my project cost 5 US$ per month, ... that's properbly less than your power bill for your Raspberry. Look into my signature for more info