FJ availability seems to come in waves. Earlier this year they loaded a ton of YVR space, basically every flight through end of season. I stumbled upon it after checking daily out of YVR/SFO/LAX for a month. I don't think you're gaining a lot by checking more than daily imo.

Also, FJ is getting a few more 350s, so hopefully the 330s will be rotated off of North America flights.