After mounting the elevators in trail position we used the bushing to match drill the horns through the VA-146 Elevator Center bearing. After that we removed the two elevators and final drilled the holes for an AN4 bolt using a #12 drill.
We reinstalled both elevators and secured both in trail position again.
We identified the most aft horn and removed again the elevators. In our case there was a minimal mismatch, with the right horn slightly back compared to the left. We defined the position of the pilot hole on the right elevator and we proceeded with the drilling of the horn.
After that we prepared a guide block using wood and two aluminium strips secured with pull rivets and we drilled the guide hole.
We drilled with 3/16" and after that with #12 drill for a AN3 bolt.
End result is very satisfactory and Lucio's support has been very valuable as always....avoiding the mess i could have done.