I think you have to fly all the Vanguards with the main gun on gimbal for that BIG ASS DEATH GATLING to be effective. Gimbals should point faster than any ship can turn, so as long as your target is in view that gun is good, and it has awesome range. Might need a special setup to point very carefully while flying. Repeat after me--"the mouse is our friend, the mouse is our friend." I know why folks don't like gimbals. They're a lot of extra work to fly a ship and separately point a gimbal at the same time, but they put that ginormous gun on a swivel for a reason and it should be able to point faster than the nose of a Mustang. This might be a reason for a touchscreen gaming machine. Would also be interesting to find out if that gun can be slaved to the second seat. That would change everything.
For the 4 fixed S2's and the turret, I think if you have to point the entire, pretty slow ship, a slow weapon that hits very hard all at once is the key and for that, the Vanduul Plasma Cannons are the thing. We can steal them off pilfered Blades and such. They are shocking they hit so hard and if you put a 5th one in the top turret and leave it fixed forward, you are doing 3,600 DPS during those few seconds you're most vulnerable. It would take some checking but my guess is that is more firepower than a Redeemer, a Connie or even a Tally. Especially against big ships the Vanguards are all going to have a place.
No, not a dog-fighter, and harder to fly well than any dog-fighter, but devastating no matter which version and with the wings blown clear off she will keep on fighting with no significant consequences. And if you really want to pimp your ride, IMHO there is no better candidate for upgrading your control thrusters.