We've been using a (somewhat modified) Autohelm 1000 connected to our
Aries for many years now. Our arrangement works well. We use it when
motoring. We also use it when there is sufficient wind to sail but
insufficient for the vane alone to work well ( 4 - 8 knots or so across
the deck for us).

Most use a small tiller pilot and attach it to the pivot hinge device
where the normal wind sensor vane 'would normally be'. (it won't work
properly unless you remove the wind sensor vane.)

We don't remove the wind vane. In conditions where the Autohelm + Aries
arrangement is best, the Autohelm easily overpowers any wind force on
the vane.

If there is enough wind for the windvane to work, there is no reason
to rig another electronic device to do the job. If you are motoring,
you do not have to save electricity and you can use the autopilot,
but in most cases the autopilot can do the steering by itself, without
the necessity to rig the wind steering gear.

As decribed above, there are conditions when we can make useful way
under sail, but the vane alone won't work. The Autohelm 1000 + Aries
arrangement draws much less power than our Autohelm 3000, and so we
prefer it when passagemaking in these conditions as our solar panels
alone can then supply sufficient power for all needs.