Haven't done it yet, but here's what I would do...

If you haven't removed the old pot yet, it is reasonable to assume contact is intermittent ONLY at a few isolated spots, where wear has taken its toll. The total resistance is unlikely to have changed significantly, and contact at other points should be good enough to take accurate measurements of 'percentage of full-scale Ohms' corresponding to distance of deflection of the metering vane. These will constitute your calibration table.

Steve