I use tie wire to mount a 2x4 about 2' long to the t-post and then the camera to that. Nail a 1x6 or other 2x to the top perpendicular to the ground for some rain cover.
Face solar panel South.
Hybrid setting check is best. If it takes a picture it connects to cellular for 5 min to send it and check for updates or on demand pictures/videos.
With the solar panel and decent sun it will run all year with out needing to check batteries.