No matter how you slice it, setting up a used R&P is a pain in the rear. What TV said is all true.
Going by the bottom set of pictures, I don't think you are far off. Hard to get the camera to focus, but it looks like the contact is a little high on the ring gear teeth. I would move the pinion toward the front of the tractor and then take one shim from the non gear side of the differential and put it on the gear side and then run it again. The book calls for the pattern to be showing on the "toe" end of the teeth which is the end closest to the differential. When the teeth deflect under load the pattern spreads across the whole tooth. That's for a brand new set and as TV pointed out, you have wear on a used set. I think the contact you have is ok where it is, just needs to be a little deeper.
The "drive" side of the ring gear teeth is what you have pictured on the bottom two that you added. "Coast" is the other side. More important to check in a road vehicle as tractors don't spend much time coasting.