D-day for the players to put down markers on the international stage ahead of the trip to Hong Kong and Australia is March 16, with Gatland then planning to announce his tour party at the end of April.
A number of individuals put their hands up for selection as Ireland were the sole nation who contribute players to the combined team to taste defeat - and they must still be scratching their collective heads as to how they managed to lose an Edinburgh encounter in which they enjoyed 77% territory and 71% possession.
On the flip side it meant Scotland, required to make 128 tackles compared to Ireland's meagre 44, remain in the running for the title thanks to a miraculous 12-8 triumph that sent them soaring to third place in the table ahead of the Irish, Italians and pointless French.
Englandare still in pole position for honours, with the possibility of the championship trophy, Grand Slam and Triple Crown on the line for Chris Robshaw's side in Cardiff if they can see off Italy at Twickenham a week on Sunday.
The French side selected for "Le Crunch" in Round 3 met with general widespread approval after Philippe Saint-Andre had come up with some frankly peculiar choices earlier in the tournament and England had to produce another composed performance to stay on track for that clean sweep.
Flanker Robshaw is making something of a habit of collecting the man of the match accolade and another display of fighting from the front further enhanced his prospects of leading the Lions in Hong Kong and Australia.
Another back rower to shine against Les Bleus was Tom Wood, while midfielder Manu Tuilagi enhanced his case for a debut Lions tour as he ignored an ear wound that required 19 stitches to score the crucial try in a 23-13 victory.
Tuilagi won his heavyweight battle with Mathieu Bastareaud hands down and, although he made a belated entry into the championship after missing the Scotland game with injury and only featuring from the bench in Dublin, the Leicester centre's impact has already been immense.
Manu Tuilagi did his Lions hopes no harm with a powerful performance at Twickenham
There were certainly plenty of positives for Stuart Lancaster to take into Round 4 but not everything has come up smelling of roses in the English garden across the first three fixtures.
While England have won only 74% of their scrum put-ins, that was an area where Wales came good in their 26-9 victory over Italy in Rome - with 2009 Lions Gethin Jenkins and Adam Jones seemingly timing their challenges for another tour to perfection.
With hooker Richard Hibbard also emerging as a genuine Lions candidate, the trio demolished the much vaunted Italian scrum to lay the foundations for a second win on the road.
Fellow former tourists Ryan Jones and Mike Phillips are others in fine form, while Leigh Halfpenny must be getting close to claiming a starting spot with his solid all-round game. His bravery and expertise under the high ball, counter attacking ability and goal kicking were all spot on in yet another man of the match performance.
Next up for Halfpenny and his team-mates is a tricky trip to Scotland - the surprise package of the tournament by some distance and a real threat on home turf at Murrayfield. And as well as telling us whether it will be the Welsh or Scots challenging for the Championship on the final weekend of action, we can expect to see numerous individual battles that are bound to have an influence on Lions selection.
Such contests will be no more prominent than in the back three where, despite Halfpenny's stunning showings so far, 1993 Lions skipper Gavin Hastings and Welsh legend Jonathan Davies are predicting that Scotland's Stuart Hogg will pip him for the No15 jersey against the Wallabies. Both Tim Visser and Sean Maitland have shown up well in their debut Championship campaigns, while Welsh duo George North and Alex Cuthbert found form with crucial tries in Paris and Rome respectively.
But while the Scottish wideman have undoubtedly shone so far, it was the grit and determination far closer to the action that led to their victory over Ireland. At the heart of that second straight success was a towering contribution in the tight from lock Jim Hamilton, and the chances of him launching his club career with Montpellier next season as a 2013 Lion will have improved significantly after he helped make a shambles of the Irish line-out in particular.
Luke Marshall was a shing light for Ireland on his interntaional bow at Murrayfield
The likes of Halfpenny, Ugo Monye, Andy Powell, Riki Flutey and Keith Earls all featured for the Lions in what was their debut international season in 2009 and who's to say that Marshall won't follow suit this summer. The inexperienced Ulster centre showed his fleet of foot on numerous occasions in his first outing and more of the same against the French in Dublin would certainly see Gatland sit up and take note.
The Lions boss definitely has plenty to think about as we head into Round 4 in just over a weeks' time, although it's safe to say that more twists and turns lie ahead as time runs out for contenders young and old.