As this is the most recent conversation on the topic;
My pinion height (E) is 26.8mm for whatever reason, vs the 26.4 specified in the manual. There are no markings to indicate an offset, and 0.4mm is quite large. That's what motivated me to make the measurement tooling in the first place, and take measurements with the original setup. Then again, per the Renault manual this configuration of pinion depth and tooth count doesn't exist so there may be other weirdness with the Lotus-specific ring and pinion set.
With the mandrel built the same as the factory tool, I'm getting approximately 52.9mm as the pinion depth with both the original and new double taper roller bearing, both with the same pinion depth adjusting washer. This is of course, 0.1mm too "tight" to the ring gear. I have on hand a pinion adjusting washer that would space the pinion back about that amount to the correct 53mm.
Considering that the differential has already worn into this spacing, and appears to have a good wear pattern,
I think it makes sense to just keep everything as-is? The side-to-side backlash adjustment should be able to compensate for some amount of wear, and prevent things from being too tight leading to premature wear.
Manual section for those following along at home, page 28If anybody needs this mandrel tooling, send me a DM and I can send it to you to borrow. It's not perfect (my lathe cuts on a bit of a taper and the tailstock is slightly off) but with a bit of care I was able to get consistent measurements that make sense. That's what those sharpie lines are, making sure the inner hole is centered to the bearing bores and not offset front or back.