Would you be hanging the personnel gate off of the pole in question? If it's going to be of similar (heavy) build to the other gate, the extra weight would help straighten things out. It would still flex when you open the gates, but everything should still line up well when you close it.
That's the basic idea but the personnel gate will be ~1/4 the size of the vehicle gate, so it won't eliminate the moment arm, but will reduce it. Although I don't think there is a foundation problem since it's about 2/3 in rock, I still plan to do a quasi deadman by boxing around the personnel gate. That will solve the problem, I think. If not I still have the option to fill with concrete. Right now it sags about~3/4" at the far end. Some of that may be the gate, rather than the pole.
I do have a ramp on the latch so when at rest it's not torquing the pole. I'll try to post pics of the latch I recently roughed out.








