I have a great deal of respect for the large laser. Now, onto efficiencies. Move the AMS ammo to the head, there's no call to have that as a vulnerability. You should probably move the Jump Jets to the torsos, since you don't want one of them to pop from leg damage. If you're dead-set on using MPLases (which, I'd downgrade them to 4 MLases in a heartbeat), I'd move them to the torso as well. That way, if you lose an arm, you only lose 30% of your firepower as opposed to 50%. (You could also make a BJ-1 doppelganger with that build).
I like the idea of the 2 ER LLAS with 4 MLAS. I only have XL220 on hand so this was my version of your build.
Here's a variant of your mech not running an XL but with basically the same configuration (downgraded ML, JJ moved to RT/LT and ammo moved to the head slot)
My variation. Never shoot the ERLLas and MPLas groups together and everything runs fairly cool. Snipe with 2x ERLLas unless the brawlers catch you. Up close 4x MPLas at a decent heat efficiency will remove legs and arms extremely fast. It's easy to leg lights, mediums, and a few of the heavies in under 10 seconds up close. If you have to brawl an assault the sh*t has already hit the fan. Hide behind something large and shiny. Look at the shiny!!!! hear: *trips Jager and runs* hear:
