First: There is no such thing as "red FM" or "blue FM". There is "the FM" and it needs to be as accurate as possible.
BUT ...
People here, on both sides, should take a step back and look at what they're expecting. I get the distinctive impression that some RAF fans want to see the historical outcome reflected in the FMs, at least subconsciously.
[Sarcasm] Hey, we won! So our aircraft must be faster, more maneuverable and better climbing!
[/Sarcasm]
And I see Luftwaffe fans who want to emulate the deeds of the classic LW aces.
[Sarcasm]They shot down XYZ aircraft! The 109 must be faster/more maneuverable/better climbing/whatever!
[/Sarcasm]
Well, to both sides,
you can't! Best you can hope for is a field as accurate as possible, everything else depends on the mission builder and the players. But, unfortunately, the overwhelming majority likes its mindless clusterf*ck.