Wind vane it's the,only way to go

I just picked up a used Simrad TP22 on ebay for about $200, had a cut wire but that's not too much of a problem to refit. I won't be fitting it to a  chartplotter/NMEA system so I just need the power lines. Not going to help with your Whitlock, though.

When you couple an autopilot to a self steering rig, are you driving the tiller with a simple windvane, or the servo pendulum or trimtab? Can it be done with either? I imagine the pendulum would would work better with light winds. If you're motoring, would the apparent wind on the vane be enough to move the rudder and save some amp-hours?

Thanks all for the responses. We do plan to fit a cane gear but haven't quite figured out what we want to go with. We want to go with an aux rudder style vane eventually. Since we have a pilot house we do not steer from a cockpit (we don't have a cockpit) and our rudder post is buried inside of the aft Cabin. We have some ideas of what we would like to build but being solely liveaboards has the drawback of not being able to do big projects anytime we'd like. 

As for our reasoning for the autopilot, Annie is correct. We sail more than many up here but with our volunteer work we end up motoring a lot to follow a transect in search of whales.  We can go with other autopilots however the mamba is said to be the best drive unit for our Whitlock steering system.