Welcome to your first FT post
1. Ex-AKL best to buy Flexi-Refund, marginally better than the other fare products, and also allows flexibility to cancel if plans change.
I am not aware of any particularly good 'bang-for-buck' routes ex-AKL. Having the ANZ Plat card is helpful for a 50% bonus of non-metal SP earn.
2. Yes, the 162 SP boost 'gift' counts as 'metal' towards re-qualification on 2024. It is
up to 20% of the of the 810 SP SPs needed to equal Gold.
If you relay on the SP gift, then it'll be a SP 'top-up' of exactly how many SP you require. So you need 240, and if you get another 78, then that maximises the 'top-up'. Worse situation would to be short just a few SP, in which case better to fly to gain the equal SPs, and then get a full 162 SP 'boost' for equal in 2024.
From what you've said:
302 needed for equal, 240 on 'metal'.
Assume AirNZ 'top up' of 162 SP.
Leaves you needing 140 total SP, 78 from NZ metal.
So, you'd need 78 from flying and the remaining 62 from credit card. If you have the ANZ credit card (50% SP earn), then a status run earning 78 SP, earns 39 non-metal. That would leave 'just' 23 SP from somewhere.
Of course, these is the barest margin for requalification, so I'd pad things.....
Read the thread on someone needing 5 SP.