I also have a Hegh'ta. It's an interesting ship. I have been flying it in a bunch of different scenarios, and while it's very fragile it's also quite fun. My front setup at the moment is 2 disruptor DHCs, 1 disruptor DBB, and 1 photon torpedo, while the back is 1 disruptor turret and a photon mine. This suits me well for a variety of different scenarios but is weak in any one of them. I dont mind, I play to have fun not to compete.
I've found that adding the dual-beam to the front was very useful--it helps me to aim the cannons by giving a slightly larger cone of fire than the DHCs have, which lets me know when I'm close enough for the cannons to work. The ship is very squirrely with all the boosts, so I try to get it in position, throw it in reverse, and let the forwards go. The DBB is *very* helpful for this. It's also useful with Fire-at-will against a fighter squad, and also puts pretty good damage on shields. I actually find the torpedo to be the least useful, even with high-yield 3, it seems like I do more damage with a group of buffed DHCs than anything else. I am always thinking about changing it to another DHC, and I still might.
Like the man said above you never need to shoot out the rear with a BOP so put something else back there. Turret would be a good choice in PVP, but I like a mine better because they serve so many purposes. They are good for killing a wing of fighters, they will killl one then change course and kill another, sometimes 3-4 in one go, which saves me from having to shoot them myself. They are also good as flares/chaff against incoming torpedoes and mines--seriously, you can drop a mine on an incoming torp and the torp will go straight for it. Turrets are very weak, I would actually put a regular beam array back there over a 2nd turret, since I could still use it with broadsides and fire-at-will. I think turrets are over-rated. But, in PVP you want to come out of hiding and put out more damage than the target can heal through, and a beam firing sideways will give you zero extra damage on the front. A weak turret out the front is better than a strong beam that wont shoot forwards.