Continuing on my quest for removing play.
Adding a shim washer to the sprag clutch/big gear wasn't as effective as I'd hoped. After re-fitting the spider the wobble was reduced but still excessive.
As others have found, the tolerances between sprag clutch and torque sensor are poor and would benefit from sleeving. On mine the little key is also loose and wouldn't hurt to be a better fit.
But the factory sprag clutches have an issue too. Comparing it to the third-party replacement I purchased, the factory item has a much larger radius curvature on each side of the inner race. This means that the flat contact area with the shaft is reduced. The replacement has very minimal curvature and is a much better fit. You can see the differences in the photo below, especially around the key way.
Looking at the wear pattern on the torque sensor, we can see that even though the sprag clutch is specified at 16mm thick the contact area is only about 10mm
In comparison, the replacement sprag clutch has a wider contact area of about 13.5mm.
Original sprag clutch.
Replacement sprag clutch.
Additionally, the torque sensor has a small protrustion that the sprag clutch sits up against. Fitting the shim here like on the older models may be better than on the circlip side.
I also experimented with using aluminium foil as a shim, this actually worked really well with the original sprag clutch. There was still play but it's within the sprag clutch and so we are stuck with it. The best I can measure is that the foil is 0.07mm thick. It was a tight fit and you need to grease the foil and work slowly or it catches and tears. I needed to gently tap mine on.
Finding shim or feeler gauge in this thickness is difficult and can be expensive, but a quick search turned up this.
https://us.misumi-ec.com/vona2/detail/110300238820/
Edit.. I just bought some assorted brass shim sheet cheap.