And here is one with N13 B0.16
The N18 pattern seems to overlay the lapping pattern quite nicely. This suggests to me that the lapping dimensions are unaltered - so no effort is made to account for any change that might happen during operation, such as a hot transmission case or deflections caused by operating forces.
The N13 pattern is really not all that different. A slight shift towards the toe for the drive side is about all I can see. Backlash did not change switching to N13, at least not within my measurement error. This suggests that the pattern is not super sensitive to pinion depth. Also not entirely unexpected.
Given the differing coefficients of thermal expansion for aluminum and steel, the pinion distance is likely to increase 0.05 - 0.07mm when the case changes from 65 deg (workshop) to 165+ deg (happy track use).
I did ask Weddle industries if I should bias the pinion depth to account for expected dimensional changes at operating temperature, and they said no, though they are just the distributors in the US from what I can figure out. Can't find a contact at Albins. Given the lack of sensitivity to reasonably small changes in pinion depth, it probably doesn't matter a whole lot. I am still inclined to go with N13 over N18 - curious what other folks have done.