Tier2 is probably the last tier where 'dual beam' can be effective on a cruiser. The things just turn too slow to use a narrow field weapon effectively.
Well I've always used some beam weapon in front and back, with the Light Cruiser I had torpedos up front first Photon then Quantum. In my Crusier I have Disrupter Beam up front and back had a Photon, then Quantum, now a Plasma Torpedo up front and Photon Mines in back. Yes, the reason I've kept that is exactly because of the slow turning ability of the Cruiser and the great 250' arc of the beams.