Mocap bone constraints

I’ve tracked some homemade mocap facial data and am using the empties as bone constraints for a facial rig on a character. Right now I’m using the damped track constraint which points the bone toward the track. I’m getting pretty good results, but I feel like I should be using ‘copy location’, but when I do that the tail of the bone jumps to the track and is fixed horizontal, and the rig kind of explodes.
Also is there a way to offset the individual tracks in the z direction? Sort ‘unlink’ it from the camera, move it, and link it back? Thanks.