That looks like a sweet spot to install the motor and gear, and easy to get to!
I've said this on other threads like this, and folks don't really seem interested, but I can't help myself.
One of the enormous values of a below-decks autopilot is that it is a backup steering system. This attribute only exists if the autopilot actuator is driving the rudder post directly, and does not depend on the regular steering system. On sailboats, they are typically linear actuators, or "linear drives," and are connected to the rudder post via a strong, bronze tiller arm. This is an expensive option, though, since the tiller arm can can be ass much as $800, and there's a machining charge to bore it for your rudder post diameter, and a keyway, if needed. In addition, the linear drive will be $1,500 to $2,000, and finally, if the boat builder did not provide it, you will have to have a very secure mounting location fabricated, solidly glassed to the hull. This work could be in the $1,000 neighborhood. By the way, I've done all of this, by mercifully the tiller arm I needed was about $400, I got a used linear drive for around $350, and yes, I paid about $1,000 for fiberglass work for the mounting pedestal.
At the end of the day, if any component of your steering system fails; the wheel sprocket, chain, wires, sheaves, or even the aluminum "radial drive" part from Edson that is so prevalent, which have been known to break, you will have a completely redundant, backup steering system through the autopilot. In addition, autopilot steering is not putting any large load on the stock steering system; and there is much less slack, or play, in the motor to rudder path, making AP steering potentially more precise, smooth, and lower power consumption, though that's admittedly a minor consideration.
Unfortunately, the subject rotary drive, gear, and chain setup here does not provide this backup, it's subject to all of the potential failures of the steering system that the wheel itself is.
I'm not throwing stones or criticizing the subject approach, as a well maintained steering system is unlikely to fail in the first place. Inspect, adjust, and lubricate (correctly!) annually, replace parts per schedule, and check for corrosion, cracks, etc., and you should be fine. But, a below decks AP that provides redundant steering is something to consider.
