ADI simulator conversion help required

Hello,

I am about to convert an old Caravelle cockpit for simulator use.
Most instruments are easy to convert using servos or stepper motors and opencockpit cards.
However a few instruments such as the ADI require much more attention.
I am a bit in trouble with the ADI which I want to move 90° left/right and 90 up/down. It cannot make any 360° on the roll as the cables for the pitch servos would get damaged.
I have tried using servos but I am not very happy with that for one main reason: Since the ADI is THE primary instrument in a cockpit the scales need to run very smoothly which the servos are not capable of with std gear. Does anyone have an idea how to smoothen a servo (different servo gear?)
I have attached an image below.
The roll index however has a complex gear mechanism which might still be used. The source wheel turns 360° while the scale index moves only 10°. Any idea how one can connect that to the computer?
Using stepper motors would require a optical sensor and the roll scale to move twice 360° which is not possible due to the cables for the pitch indicator.
So far I am using opencockpit cards.

I would very much appreciate inputs and ideas.

Best regards

Nils

SudAviation.com - Caravelle Website