Given so many tracks are damaged, I was thinking of using the Homepin HV board.

Overlay boards are a good way to get some more life out of a board. I keep one next to my test rig, when I get a faulty board in for repair, I throw a overlay board in circuit to make sure the board doesn't have a logic problem before I do a HV rebuild. I find most times, troubleshooting the logic isn't cost effective, so if a board has a logic problem, I set it aside for 'some day' when I have more time.