for the most punishing Alpha you'll want to be a Tac. GDF -> ApA -> TI -> TT -> EptW -> Decloak and attack.
You will need to spec into Phasers, cannons beams and use x2 Phaser Relays (boost canons and lance).
2x single cannons (broadside backup because it will happen)
2x dual heavy or 1 dual heavy / 1 torp
Aegis Impulse Engines (buff to combat manuvers gives total of about 10% to your total damage on alpha. and 5% defense)
AMS (or whatever you desire)
TT, or HY
EptW, ET (or, AID, Extends), EptS, WP
EptW, AID (or RSP), EptS
ST, Hazard Emitters (or Hazard Emitters, and TSS 2)
Note, Aux to inertial dampeners is used for the large manuverability gains, 2x copies means 66% uptime. Your DPS will be sub optimal Vs. Beam cruisers similarly configured, not recommended for PvP, but you shouldn't be a liability in an STF either.
Your need for Aux to Dampeners will vary based on play style but to manuver to line up your cannons this is a good base (IMHO). If you are an engineer your power needs will vary so you might be able to drop the emergent power to weapons. As configured you should be able to run 125 power in weapons and shields indefinitely after the first 15 seconds. For a pure cannon cruiser the excelsior has the better BO layout.