If the rear turret can turn well, mount a gunboat turret / solaris on it. In fact, if you're going 5 turrets and 1 missile, put the missile on the front fire arc one (hardpoint one) then mount your turrets on the rest. Fighting in rear-view is surprisingly effective, as you can strafe to avoid supernovas and still dish out a lot of damage.
I've heard a lot of good things from people who've used that ship a lot on 5 primary turrets and a missile. I've experimenting with a forward and a rear missile with 4 Zoner Turrets, but I haven't experimented enough to know for sure. A rear missile seems to work quite nicely though. Maybe the front should be a Razor then?