If you're flexible I'd suggest the NZ domestic legs either in the weekend or middle of the day (ie not early morning or late afternoon). Will be less full, easier check-in, etc.

If you get to *G status by the time you get to NZ be sure to check out the lounges [insert link to NZ lounge thread here]. SYD, WLG and AKL in particular are very good. Or else befriend someone else who has access and can invite you as guest

If you want to catch up with other FTers in NZ there is a itinerary thread in the NZ forum.

If you had a few more miles to spare I'd suggest a visit to the pacific islands since you have come this far anyway it would be a shame to miss them. OTOH with the introduction of Pacific Express fares you could add a side-trip (ie separate to the RTW) for a reasonably low amount.

Hope this helps.