I have a mossberg 500 youth. 20 gauge. I'm going to be shooting tss 7 and 9 shot. Am I better off with Indian creek ported choke or Carlson tss non ported. I've read a lot of things say porting makes no difference. Both are .555 constriction. Does anyone know what the factory xfull mossberg choke is? I found 1 thing saying .585