Pretty much everywhere I’ve hunted, panels (your manufactured jumps, coops or post and rails) are installed by the hunt club, with a landowner’s permission, at strategic locations in the fence line. The fences were there first, and serve a purpose, usually to keep livestock in. As you note, jumping wire is not for the faint of heart, so panels are installed so that hunt followers can stay with hounds but still respect the landowner’s use of land. When hunting new country one really has to hunt it a few times (go through gates, or jump the wire:)) til one gets a feel for which way the quarry tends to go- then you can arrive at the best locations for the panels.
Only place I’ve ridden where you have the choice of jumping, or not, is the Hitchcock Woods in Aiken- drag hunt there- and one has jump height options, or you just go around as they are set in the quite wide paths.
When I helped build jumps in VA, we built them at 3’6" and they tended to settle over time. A 25 yo coop might wilt all the way to 2 feet. BUT- if they are not built high enough to hold livestock, then you need to install a rail over the top, to be lowered before jumping and put back after jumping (or, some of us just didn’t bother and jumped the rail). Cattle have no problem jumping 3 feet, or even 3’6" if they have a mind to.
At least one hunt out in Colorado ‘panels’ by simply putting PVC pipe over the strands of barbed wire. Seems to work well but you need to like jumping vertical fences!