The problem with "Davy Back fights", is that some SH's are gonna lose.
Since one of Luffy's declarations was "to form a crew that would surpass Shanks' crew", I wouldn't make them lose at any time.
Even though, a fight with Yasopp and Usopp providing long range support while, idk, Roux and Sanji or Zoro and Beckmann fight, would be dope.