I see why fixed on top and Gimbal on bottom on a Cobra. Can I ask whether people favour Beams on top or MC on top in the Type 2 slots?
The problem with gimballed beam lasers on the lower weapon slots is their position under the wing tips. They can't hit anything above halfway on the HUD. When they lose their firing solution, they just point forwards, but keep using power and generating heat. Gimballed multi-cannons still cannot hit a target above the midpoint, but when they can't see their target, they stop firing.
Fixed beams in the lower slots have another issue. Due to the positioning of the wing tip hardpoints, the beams are angled inwards but not to the middle of the targeting ring. In fact each lasers target crosshair lies outside the targeting centre. This leaves a large gap between each laser's fall of shot, which means that unless you are pretty close up to a large ship, at any given time one of the lasers will be off target. (Tested last night on Beta 1.2).
I use a D2 gimballed beam in one medium slot and an F2 gimballed multi-cannon in the other. I have 2 gimballed G1 multi-cannons in the lower weapon slots, that automatically join in with firegroup 2 (multi-cannons) when they have a firing solution to do so. This adds useful kinetic firepower, without energy or heat problems. The single D2 laser can be used in sustained bursts (as it is the only beam weapon firing) (and the only weapon producing a significant thermal load), keeping track of ships in a fly-by as well as head-on.
This is what I have found works for me.
I tried missiles in the lower slots (of both types) but just found that I didn't use them.