Agree fully with Bill.
I took my hydrovane off and sold it. I would have loved it on my previous boat (Jeanneau 37). I'm not the best sail trimmer and if the boat went off course it meant releasing the locked steering wheel and getting the boat back on course - or - going to the back of the boat to disengage it. At night this was more of a problem. The rudder on it is vertical and is great at gathering sargasso weed. So even on autopilot it can be a pain. The hydrovane rudder is very difficult to put on in a seaway so you have to fit it before departure. It is easy enough to remove under way but not to replace it.
As an ever ageing couple of was obvious that 'we' on this boat didn't need it. We just carry a spare rotary drive.
If you do install a hydrovane reinforce the transom. It wasn't built to take the forces of the mounting struts.
Ocean Hobo SN96