I've found this with both my ARS808 and a friend's RMG. The trick that I found was to start fiddling from the centre of travel. What I mean by that is that you remove the winch drum, set the end points on the winch "equal" (i.e. both, say, 100). Set the winch stick to EXACTLY mid-position so that the winch itself is mid travel, then power off. Next move your sheet clip to EXACTLY the mid-point of its travel. Next, fiddle with your winch drum so that the sheets are still midpoint and get your drum back on the winch as close to that mid position as possible - don't put the screw in yet. Now, with the transmitter stick still mid travel, power everything back up, and GRADUALLY test the travel in both directions and adjust the endpoints so that your range of travel is correct and both endpoints should be within one or two of each other. Take care with this stage because if you sheet in or out fully you may wreck the pulley blocks amongst other damage, slowly and carefully is the watchword. On both the IOM's we moved from a single click on the winch stick (Futaba T6K) resulting in 1cm+ of sheet movement to small mm's of movement and even across the range of travel.