Using Dual Beams may seen like a good idea, but overall, 6-8 single beam arrays work better.Your turn rate is not _that_ good - and investing in your turn rate to be that good is wasting healing and resistance potential.
4 DBBs, with 4 turrets aft go bo3, and bo2 with Tac Team to finish it off.
Run 2 Aux to dampeners. Though this setup -only- works for a tac captain in my opinion since you need the boost from APA, and GDF to make the dps worth it. I also recommend EPTS3, and Warp Plas 3 with ASIF3 as an alternate boff choice. 2 EPTW1s, and in the ensign run EPTS1. This also will allow you to run a fairly exotic power setup which will enable you to have almost max weapon and shield power at all times. (I believe you will want to set both of your sliders to 75 for shields and weapon power, once you run a +7 shield and +7 weapon power consoles.)
TSS2 and either a TSS1, or Hazard emitters, with an aux battery to spike it when you need it. Hazard gives you a strong hull heal when spiked with a good damage resistance.
It's a pretty nasty ship, as aux to dampners is now perfectly chainable again, making you immune to stuns, and repel effects constantly unless you are SNBed, and aux to inertial dampners also greatly increases your turn rate. I also recommend one RCS console with the setup to have an even work able turn rate.
your last console slot should be the +35 percent to shields of course.
Due to the superior inertia of the excelsior (to every cruiser out there) warp plasma is much easier to use, and you will find it quite valuable in keeping targets in your Prime DPS arc, as well as keeping escorts off your back, as you can make a cloud and nestle your ship inside of it, if necessary. Once you get good at deploying the Warp Plasma you can routinely snare entire enemy teams in place, inflicting the dot on them, as well as robbing them of a defense score, in addition to keeping them in your forward arc once you perfect a flat spin to get your ship 180 degrees around.
With proper use of Evasive Maneuvers, and all of this people will have a rather difficult time in effectively dealing with your ship.
I also recommend you do the STFs, to get the borg gear, as Aegis is quite simply Terrible. And the borg proc gives you a very strong hull heal to round out your setup in addition to gaining a very strong shield heal.
You may also want to consider Resilient Cap 3 shields, as an alternate for the Borg shield, as your hull healing is very limited with this setup. (but the damage capability is very strong)