England host world champions Germany at Wembley on Friday and Brazil four days later.
The depleted squad allows Southgate to field a lineup from a pool of youngsters including Tammy Abraham, Joe Gomez and Ruben Loftus-Cheek, who received their first call-ups to the senior squad.
"This period between qualification and the finals has to have an element of experimentation," Southgate told a news conference on Thursday.
"If we don't try things in these games, when are we going to try things? Germany took a really young team to the Confederations Cup - I thought it was brilliant what they did.
"I've really enjoyed the week. New players coming in and two great games to look forward to. We'll take more from these games than any of the qualification games."
Southgate dismissed any talk of a club-versus-country row over players' fitness.
Spurs manager Mauricio Pochettino said on Wednesday his top scorer Kane would be fit for Premier League trip to Arsenal on Nov. 18.
Asked if he was satisfied that all players who had pulled out were genuinely injured, Southgate replied: "Yeah, absolutely.
"I hear this talk of club v country -- it's nonsense. They are injured and they can't play. Harry Kane -- I knew he was in trouble because he stayed down -- Kane doesn't stay down.
"...Spurs might risk (him and Winks) them for the Arsenal game, that's a different matter."
England host world champions Germany at Wembley on Friday and Brazil four days later.
(Reporting by Hardik Vyas in Bengaluru; editing by John Stonestreet)
