A wheel pilot would be your best bet if the
helm is light. They have gotten quite sophisticated in their
electronics to cut down on amperage and increase responsiveness. Cost a little more than a
boat unit and are easy to install and use. The usual suspects make them like
Raymarine. Even though they are not really designed for heavy duty use, people have crossed oceans using them. These are not suitable for boats that have a heavy
helm, though. The
Raymarine X5 steered my
boat fine under power and days on end but would only handle the boat under sail in light air. The
motor would stall out with the heavy
weather helm as boat speed increased.
The CPT has been reported to have plenty of oomph to steer almost any boat but the
electronics are/were basic. They may have made recent upgrades as I think the company was taken over by new blood.