My go to energy build on the RGH chasis (3A variant is better suited but I don't own it yet). Yes yes people, I chose LL over LPL, go figure. The topic has been a major one in my unit as well. With me being fairly alone in the defence of the LL over the LPL,... go figure some more,... But I keep my stance. The build is just as fast, more surviveable and features better heat. I just do better in it.
I think that the whole point of LL is to maximize damage over tonnage. Your build should work because it does (or it should have: I don't own this chassis but I do own the 3A vomit laser variant w/ 7 energy hardpoints) have very hi-mounted and very good hardpoints, which means that if you play it correctly (minimizing both exposure and exposition time) you will probably take little to no damage despite the longer laser duration. You could spread the damage more compared to a LPL, but you will be cooler and have still good DPS over heat generated.
LightEngine300 for more DHS. I know, I used ERLLs instead of standard; swap 'em out, they're interchangeable. I do think, for a build design like this, with the BEAUTIFULLY high mounts this 'Mech has, it serves well as an ERLL boat. RocketLauncher15 just b/c it had the slots. Drop it for more armor as you wish.
And here's that 4LPL version. Had to change to light ferro and shuffle some stuff around to avoid dropping to an LFE265. Alt with standard armor. Slower but cooler with a little more armor.
As of the April 2021 patch, I'm going to be running this in my Reaver, as ghost heat limit of LLs is now 4 (though can always fire in 2+2 anyway). The ballistics in the arms are just too vulnerable and low for the tonnage you spend on them. Single mrm10 is for fun and because I had too much heat dissipation.