I only started using OMG a couple of weeks ago so a bit green. Maybe you could try and contact gareth who has done a lot of work with the watchman,
Well, I have picked up hundreds of car tpms readings now, and I even caught a couple of watchman readings which I was very excited about for a short while, but then I figured from the reading that these must be from next door. Their tank is about twice the distance away that mine is, so I am fairly convinced that I have a variant that is not coded for at the moment.
I think the only way forward now is to get a 433 usb tuner stick and plug that in to my home assistant Pi and run rtl-433 on there so I can (hopefully) catch the raw signals and see what is going on.
I have a NoElec SDR running on a Raspberry Pi with RTL-433 in the same location as my Lilygo. The Lilygo with FSK picks up all the local Watchmans, at least 4 or 5. I had to take my watchman out of the tank to ID it. It also picks up the odd Renault TPMS but we’re on a quiet street. The SDR with RTL-433 picks up all the Watchman traffic and lots of Oregon Temperature sensors on the default config so it’s seeing FSK and OOK together. I’ve not researched how to put it in RAW mode yet. I did pick up one Watchman Pro message on the Lilygo that was decoded differently so it is seeing a different type of Watchman that is further away. If your Watchman is close and compatible I’m sure you would see it as I see 10-15 readings per day from each local watchman