Quick question (although it might be a long answer!)...

The reason for using electronic gearing here is because you want to include the controller in the feedback loop but it can't handle the encoder pulse rate (as I understand it). In this case, is there an argument for using step/dir signals to the servo controller (which most of the ones I've looked at seem to support)? OK, controller is out of the loop but the servo controller can handle the encoder feedback itself, possibly with some kind of built-in auto-tuning (guessing here) and maybe give better overall performance? Or maybe I've misunderstood completely and this is about using analogue input controllers?