Just looking for some clarification and discussion.

I was recently informed that the passengers side bank (Aussie vehicles) of cylinders regularly run leaner than the drivers side.

This info isnt something Ive experienced (Ive only ever used WBO2 from one bank) nor something I remember reading in the past.

A mate used the pass bank for his VE tuning only to run it on a dyno to find it approx 0.4-0.5 of an AFR point rich when the dyno operator logged his afr.

The dyno operator, who is also a respected tuner, suggested to use the drivers side bank for WB02.
He did this and found the difference was approx 0.4 of an AFR point richer when compared directly to the AFR's of the passengers bank of cylinders. (SFA diff in hp/tq when the tune was adjusted that 0.4 AFR too)

Is this info something previously discussed? (the search function didnt reveal anything).

Secondly, which bank should be used?
I would argue that the pass side be used. Id prefer to run a little richer on one bank as opposed to a little lean.