The host team in Hamilton will be different again and although Ireland coach O'Sullivan admires Graham Henry's range of options, he will not be adopting such a system.
On the team's arrival in Auckland, O'Sullivan said: "You don't mess around and experiment in the southern hemisphere against teams like New Zealand and Australia.
"We're here to try and get a job done and put the best team on the field we can in each game.
"Graham has got that sort of strength in depth at the moment where he can do that and I think most coaches in world rugby would like to have that latitude.
"What he's got to do is make sure he wins all his games and when you've got a schedule like New Zealand have you maybe have to work your squad a bit.
"I would like to do the same sometimes but we maybe don't have that latitude and the most important thing in Test rugby level is to win."
Henry has a concern over stalwart lock Ali Williams. The Auckland and Blues second-rower suffered an ankle injury in training and Chris Jack of Canterbury Crusaders has been pencilled into the 25-man squad for the two-game series.
Williams and Jack have been the recent number four and five pairing for the All Blacks, so Blues duo Troy Flavell and Greg Rawlinson will form a novice duo at Test level.
Flavell, nominally a flanker, has spent several years on the outer fringes after a spell in Japanese rugby and disciplinary problems in his previous All Blacks career.
North Harbour's Rawlinson will be a Test debutant after the Durban-born forward qualified for New Zealand residency.
Prop Neemia Tialata is likely to be fit for the first Test despite injuring his knee injury in the Super 14 final.