England captain Eoin Morgan says he still does not know his best team despite having only two scheduled games remaining before the World T20.
Morgan's side, who completed a series whitewash over Pakistan, are unbeaten in five successive T20s heading into the global tournament which is being hosted in India in March.
"I don't know what my best XI is but it's not a concern," said Morgan, 29.
"The rationale behind our rotation is long-term development."
England completed their first series whitewash in the shortest format when they beat Pakistan in a super over on Monday.
Sussex all-rounder Chris Jordan was named man of the match after keeping his composure and conceding just three runs in the one-over shootout.
Hampshire batsman James Vince was man of the series after scoring 125 runs in the three matches while Lancashire spinner Stephan Parry, Yorkshire fast bowler Liam Plunkett and Kent batsman Sam Billings also impressed.
"With the rotation throughout this series we can go through a stage of picking the guys in form from 15-17 names," said Morgan.
"That breeds a good culture and the guys are really buying into it. We've seen such good performances throughout this tour."
Who are England's other options?
England play just two more internationals - both against South Africa - before the World T20 begins on 11 March.
They will only take 15 players to the tournament, and fast bowlers Stuart Broad, Mark Wood and Steven Finn will all hope to be in contention.
The selectors are also likely to recall all-rounder Ben Stokes, meaning some of the players who helped beat Pakistan could still miss out.
"We've seen such good performances throughout this tour," said Morgan. "James Vince has not let us down once in three knocks with the bat and has been our player of the series which is brilliant.
"We've watched some of our bowlers and Chris Jordan, Adil Rashid and Stephen Parry and Moeen Ali all bowled really well so it will make for some difficult decisions when it comes to selection for the World Cup."
Referring to England's lack of a franchised T20 competition to rivals the likes of the Indian Premier League and Australia's Big Bash, Morgan added: "We don't have the privilege of a very good domestic tournament so don't see these guys under much pressure - they only get it with some derby games and on Finals Day.
"We've been playing in similar conditions to what the World Cup will be like in India, facing a lot of spin so it's great to win this series."