So as noted here I have executed the first part of my plan.

I've booked, all in PE, SYD-AKL-SFO with my intended dates and LAX-AKL-SYD with dummy dates, which I'll change once bookings open for the return date I need. I managed to confirm upgrades to BP on AKL-SFO using my RUs, which was the object of the exercise, so that's good. However our SYD-AKL upgrade (using Elite APD upgrade request) is waitlisted, and my guess (based on previous SYD-AKL upgrade requests) is that it remain that way until much closer to the time.

Assuming that SYD-AKL is still waitlisted when I slip back down to Gold in a couple of weeks time, what happens then? Is the request still valid and processed / prioritised based on my Elite status at the time of requesting it? Or would it slip down the priority list to be considered alongside Gold RUs from around the 6 day window?

As a side note, the SYD-AKL flight is on a 77W which currently appears to be absolutely wide open (not a single seat sold in BP I don't think, which would make sense since it only went on sale a few days ago). Does anyone else have other data points re when R class is released on shorter sectors like SYD-AKL? Is there any point in calling the Elite line some time before I drop to Gold and seeing whether an upgrade can be requested manually? Does that ever happen? (I know that the auto-waitlisting is known to be buggy if R class comes available but at some date after submitting your request but before revenue management is actively monitoring the flight, so just thinking about how to maximise our chances. Though at the end of the day, PE is perfectly fine for a trans-Tasman hop.)