I read here about people checking in and discussing or making requests about pending RUs (eg saying it would be ok if only 1 passenger out of 2 was upgraded/happy to sit separately).

How exactly does one make such requests when checking in overseas?

In my limited experience, airports in Asia use non-Air NZ staff at check-in, and there are no Air NZ staff at the designated lounge.

Meaning that the first contact with Air NZ staff is at the gate. Would I need to go to the gate early to discuss still pending RUs? (And is doing so at the gate potentially a bad idea/liable to reduce chances of success)?