I will probably add rudder to mine or build another one so I can do knife edge and some other stuff requiring rudder imput.
I've not flown a dogfighter, but I've built three spads with similar dimensions. You will probably not be happy with the dogfighter trying to do a knife edge. The short tail provides very little rudder authority, and the fuselage provides very little aerodynamic lift from the side. As has been previously stated in this thread, the dogfighter is a combat plane, not precision aerobatics.
But good luck trying!
Brad