Air NZ seating question

[Ben W]

About to book tix's through United on Air NZ back to Melbourne for Christmas and had a seating question for anyone that has traveled with two young kids (twin 4 year old boys in my case). I have the option of flying a 777 from SFO with 3x3x3 seating, meaning I can prop the kids up against the window in back to back rows with a parent in the middle and a stranger in the isle.

The other option is the 747 from LAX where we could use the middle 4 seats. Price is the same and flight time is close to the same...give or take 30 minutes. Just wondering if anyone has preferences or advice for which would be the better (or should I say easier) option?

Thank you,

Ben