Stuart Lancaster now views the first Test of England's tour to New Zealand as an important source of guidance as he ponders the composition of his World Cup squad.
Lancaster is almost certain to name an unchanged starting XV for a third successive match when Ireland visit Twickenham on February 22 in a fixture pivotal to the Six Nations title race.
A 20-0 rout of Scotland and narrow defeat to France means Lancaster is unwilling to tinker with his line-up, stating "it's looking relatively settled".
Wing Marland Yarde, centre Manu Tuilagi and full-back Ben Foden are due back from injury before the Six Nations ends, but should England continue to impress they are unlikely be involved.
Until recently Lancaster regarded the opening Test of the series against All Blacks, scheduled for Auckland on June 7, with trepidation due to the absence of those players involved in the Aviva Premiership final a week earlier.
Now, however, he is grateful for the all-too-rare chance to test the true limitations of his squad building.
"The more I've thought about it, the more I'm quite enthused by the opportunity to give others a chance," England's head coach said.
"We had a training session the other day where it was 15 on 15 and I looked at the team that were starting against Scotland and I looked at the second that were training against them and it was pretty good team.
"So for that first Test in New Zealand, it's not a bad thing that someone else is going to have to start for England in order to evolve our depth."
When asked if his 'ultimate' XV had changed in response to England's performances in the first two rounds of the Six Nations, he replied: "Yes and it will continue to do so.
"I expect the core of 35-40 players to remain the same, but as for who is in the 40 and who is in the starting XV......
"A World Cup is not won by 15 - only three players in New Zealand's team played all seven games.
"I have an evolving spreadsheet that changes. It's in my mind as well."
England have 18 games until their 2015 World Cup campaign on home soil begins, leaving Lancaster with few chances to experiment as he balances the twin needs of developing his squad with winning.
"I need to create opportunities for other players, but not to compromise the team's chance of success the Six Nations," Lancaster said.
"Not too long ago I did the hypothetical exercise of looking at composition of previous World Cup squads.
"How you balance up that squad is important and you soon realise that decisions will get very tight. It will be competitive, no doubt about it."
The visit of unbeaten Ireland, who have swept aside Scotland and Wales, will offer an invaluable guide of just how good the current England XV are.
"Ireland are becoming the most complete side, definitely, because they've clearly improved in their forward play," England's head coach said.
"John Plumtree is their new forwards and defence coach and you can see the improvements they've made in that area.
"Their mauling game, as we saw against Wales, was excellent, so technically they're very good.
"They're very good at the breakdown, which is another element of John Plumtree's role.
"And Joe Schmidt is a very good head coach who understands the different strategies needed to win games.
"Ireland have kicked the ball probably double the amount of times they did during the autumn internationals. They manage the tactical game very well.
"The third part of the equation is the quality of players they have.
"There were over 700 caps in their team and you only have to look at how many British Lions they have. It's a pretty good side all round at the moment."