Mode Zero

I would like to convert a number of climax servomites to proportional control for use with a reeduino. Modern servo amps are no problem to fit but the wiper end stops need to become feedback pots. Some early linear servos had wirewound pots epoxied in the amp board. Are such wirewound pots still out there and what value should that be.
Clive

I have 4 climax Musclemites that may convert with less problems there just a bit big. I would like to get hold of the original RCS reed servos, I have 2 and 1 in a poor state of repair. wonderful looking device nicely made.
Clive