Additional Information: I found, that in a Federation Cruiser, it is extremely important to be able to continuously score hits on an enemy vessel; especially when a fair share of enemy vessels are Birds of Prey mixed with a plethora of small fighters and drones.
For that reason the following skills and Traits are also important in my opinion to any Good Cruiser using Beam Weapons:
Character Innate Trait: Accuracy (+10% to Accuracy Modifier)
Starship Targeting Systems: 9 ranks = +99% Accuracy Modifier)
I have noticed precisely that: DPS actually goes down beyond 4 beams - and thus, I usually equip something like 2 beams, 2 torpedos fore, and 2 beams, 2 torpedos aft when commanding a cruiser.
On my cruiser, I ran a setup with 1 Rapid Fire Torpedo Launcher and 7 beams. I powered them using a combination of max weapon setting, Emergency Power to Weapons 1 and a Warp Core Engineer doff.
My weapon power was high enough that even that 7th beam added some dps. And the rapid fire launcher allowed me to keep broadsiding while firing torpedos, thus keeping the damage active all the time. It worked very well for me personally.
I run a galaxy-X so alot of my firepower comes from the front (due to the phaser lance) but normally on cruisers I'll have this set up.
Front- 2 beam arrays, 1 dual beam, 1 torp
Back: 3 beam arrays and a torp/mine launcher
If i want a bit of extra punch in the front I will replace one beam array in front with another dual beam array. This works well for some of the more agile cruisers and i dont have to worry too much about power bottoming out.
For a bit of fun this thread inspired me to drop one of my 8 beams as I raved about earlier and try a photon up the front.
For the D'kore its a great option (torp spread 2 and the nadeon detonator console) and i find i dont lose much dps at all. I do still cycle EPt Weapon 1 and EPt shields 3 & 2. However i doubt i would use this build on any other cruiser as i have to choose between 1 load of torps or a FAW and the D'kore with battle mode is build for something like this.
* I use the Odyssey and Assault Cruiser on both my engineer and tactical officers. My tactical officer also flies an Excelsior sometimes.
* I cycle EPtW1 and EPtS3 with both toons, using Nadion Inversion when I have a need for 30 seconds of high-level pain output on my engineer. This results in weapon power that is nearly 125 at all times, except when firing.
* Currently I tend to pack six beam arrays, two torps (3 beams, 1 torp per side).
* I'm thinking either 2 beams, 2 torps per side, or fore: 2 arrays, 1 dbb, 1 torp, aft: 3 arrays, 1 torp