With slower plane (that is more maneuverable) I either gain the advantage in altitude and make a slower dive from behind to hose the fuselage (hopefully killing the gunner and knocking out the fuel tank/radiator), and contrary to short bursts, I shoot long bursts (RoF actually makes guns jam on short bursts rather than long ones).
Alternatively I sneak up from below and steal enough pot shots that I can take out the tank/radiator.
Either way, when I get the target leaking, there is no hope for it, I simply leave it alone to land/crash instead of facing a ferocious rear gunner
If I get the gunner on said pass/pot shot, I try to finish it off sooner, but not if there are enemy fighters around.