Cape Town - Red-hot Cheslin Kolbe or the sizzling S'bu Nkosi?
If Springbok head coach Rassie Erasmus is determinedly going to consider the pair as right wing options only, he has the most pleasant of quandaries on his hands, really, in deciding which of them earns rights to the No 14 jersey for the major clashes at looming RWC 2019. Or does he?
One enticing way of dodging the dilemma, and already being discussed in some earnest by observers, would be to shift one of them to the slightly less familiar terrain of left wing, even if that would mean sacrificing another lively, emerging customer in Makazole Mapimpi.
Despite Mapimpi's own appetite and thrust on attack, his defence remains the subject of some scrutiny and, on an overall basis, the two "form" fliers for the Boks out wide this season have almost indisputably been Kolbe and Nkosi.
Each has started two Tests on the right - Nkosi against Australia in Johannesburg and Argentina in Pretoria, and Kolbe against New Zealand in Wellington and the Pumas in Salta.
The quality of service from them has been seldom less than exceptional, going quite some way to explaining the Bok sequence so far in the international season of three wins and a draw, and the Rugby Championship title in the bag in the process.
While Nkosi earned very comfortable player-of-the-match status for his critical brace of tries - both more determinedly and cleverly engineered, the more you re-watch them - at Loftus last Saturday, the little terrier who is Kolbe had been just as dynamic and wholehearted in his brace of appearances.
So what now?
It is widely expected that Erasmus will put out his "first team" in the last Test before the World Cup starts, against Japan in Saitama on September 6, just over two weeks prior to the huge tournament opener against defending champions New Zealand at Yokohama.
While there will be other head-scratchers for him - such is the healthy level of competition in various positions - before he reveals his desired selection hand, that "Kolbe versus Nkosi" one could top them all for tough call.
Frankly, he would not encounter too much dissent if he opted to use the Japan date as a late trial for one of them (Kolbe is arguably a better bet, given his already commendable versatility within a backline) on the other side of the park at No 11.
While some experts - including 109-cap midfield legend Jean de Villiers, who played a few of his Tests on the wing - have cautioned about the specialist demands of the different wing slots, another Bok icon in the shape of Bryan Habana has proved previously that it is possible to prosper on both wings at international level.
While the No 11 jersey will always be the one he is most remembered for wearing in his glittering career, Habana became no less comfortable at varying times with the cares of the other wing.
It is where he also registered more than a few of his 67 Springbok tries; a hat-trick there against the United States in London at the 2015 World Cup comes to mind (when the less positionally flexible Lwazi Mvovo was deployed on the left).
There is no special reason to believe Kolbe would look a fish out of water on the left wing, especially given his rich knowledge of the fullback role and its occasional demands, either defensive or offensive, down either side of the touchline.
He has always had an excellent rugby brain and advanced sense of awareness of situations during play.
It just seems a crying shame for the Boks not to have Kolbe and Nkosi on the field at the same time because they have been pigeon-holed for the same specific role.
They would in all likelihood complement each other well if a wing alliance could be made to work, with Kolbe's elusiveness and swerving skills a fine foil for the more power-driven - though not exclusively so - attributes of the strong-thighed Sharks man.
Both are also increasingly tenacious customers in high-ball contesting.
While memories of the shock Bok loss to Japan at Brighton in the last World Cup remain unpleasantly vivid to many South Africans, it is highly unlikely that lightning will strike twice in the early September meeting; Erasmus's confident charges should put them away with a bit to spare this time.
Against that backdrop, isn't it at least a suitable, relatively low-risk opportunity to put in a toe in the water, as it were, with Kolbe at left wing for the possible benefit of deeper Bok aspirations shortly afterwards?