Back when I still had cows, in some places I would run electric fence, 2 strands one about knee high the other eighteen inches or so above the other first one. Tie strips of cloth, plastic bags or something where you and other can see the wire. Use T post and insulators.
If you are going to put up barb wire and if you can get though there easily, borrow a post hole digger for a tractor or the complete rig for your wood post, you can put up the T post with a post driver. I don't know about where you are but here You can get on a list with local electric company and they will call you when your turn comes for some free used light poles. For 4x4 post or smaller around here 2 ft deep is usually enough. If going with barb or net fence brace corners and places between ever so far. If it goes up and down hills you will need some of the bracing along. /I\----T----T----T----I=I----T----/I\ Some of my cows were huge, I saw one come up to the fence Regular net with 2 strands of barb wire, she leaned over put her head over the top strand to eat on the other side. As she ate and pushed against the fence she broke 2 lightered post off a the ground while I was hallooing at her.
Good luck with which ever you choose.