Torsion bars

Yup, pretty easy to explain, just torque the pivot nuts with the LCA's at the same angle they'll be at ride height. Definitely easier said than done.

Another reason to like Poly or Delrin LCA bushings, the bushings rotate on the pins, they can be torqued anywhere.

Wouldn't it be less risky to just tighten it with a ratchet while it's on the ground and then use the torque wrench once it's in the air?

I feel like if you're a little off with your angle while you're in the air, then you're going to have that amount of flex once it's torqued and on the ground. Whereas tightening it with the ratchet on the ground should be sufficient enough to hold the LCA at the correct angle once you're in the air and ready to torque.