Due to lack of ballistic quirks, ERLL will contribute a lot to the overall DPS. Also, due to longer exposure this mech won't last very long against returned fire... IMHO 5 tons of ammo should be enough for most QP games, so you can swap that 6th of ammo for an additional DHS and improved cooling. _
1.85 seconds is a long time to hang out there. What to you think about eating the ghost heat for 3 ERLLs and putting the extra tonnage into engine/heat sinks? 43.9 heat (three with ghost heat) vs 47.2 heat (four) More damage on target early, which is when the damage is really going to matter most of the time. You may be wasting some of the burn time on all four lasers anyway some of the time when the target or you get back in cover. _