A few pointers:
As has been said: Eve Workbench is a collection of weird stuff with the odd good idea in it. If you can’t tell the difference you can end up with a bit of a lemon. It is a shame that Eve University is dropping their fits, but I can understand why.
@Do_Little’s fit is sound (and interesting: I’d’ve not put a Large Battery on an Omen, but it does work - at my skill level I’m Cap Stable with everything running, and 300+ dps at 15km. I don’t like small repairers on cruisers, but that’s my preferences.) - yes: 25m ISK at Amarr on current prices.
For reference, the Coercer @Random_Rick is using is:
Coercer
[Coercer, Valiant]
IFFA Compact Damage Control
Small I-a Enduring Armor Repairer
Extruded Compact Heat Sink
5MN Quad LiF Restrained Microwarpdrive
Eutectic Compact Cap Recharger
Dual Modulated Light Energy Beam I
Dual Modulated Light Energy Beam I
Dual Modulated Light Energy Beam I
Dual Modulated Light Energy Beam I
Dual Modulated Light Energy Beam I
Dual Modulated Light Energy Beam I
Dual Modulated Light Energy Beam I
Dual Modulated Light Energy Beam I
Small Semiconductor Memory Cell I
Small Energy Collision Accelerator I
Small Energy Metastasis Adjuster I
Imperial Navy Standard S x8
Imperial Navy Radio S x8
Imperial Navy Multifrequency S x8
It should be good for 200+dps at 10km (Navy MF), 150+dps at 20km (Navy Standard) or so.
(I can understand the view “don’t use faction in missions”. But the extra damage is useful).
Personally, I’d say have a go at cracking Dagan with the Coercer you’ve got - bail to a safe spot if you need to repair and let the capacitor recharge (don’t leave it too late!), but it should break him reasonably efficiently.
Sensible upgrades to that Coercer if your skills allow are to uplift the Heat Sink, Damage Control, Recharger and Repairer to T2 parts (probably in that order - I prefer damage over defence). It’ll be cheaper than a Cruiser!
Fleeting up with others is also a good idea: a pair of you in destroyers will smash through him quite happily.