While I was waiting for the next set of prints to finish, I took a look at the pushrod.

The garden stake I had previously used was getting rusty.  I went looking for a replacement and locally sourced a few carbon fiber rods and some AL tubing on clearance.

Only found an extension spring of the right inner diameter, but it quickly became a compression spring with some excessive force.

This telescopic combination let me move the weight of the spring from the top of the pushrod to the middle, where it's mass will now be closer to the center point of rotation for the tripod kinematics.  In other words, it won't move as much, and so it's inertia will be less of an influence on the head.