Something about the visage of the Boar's Head made me think of Orcus (the god of the underworld)... After much tweaking I started to love the XL400 engine. I find an atlas moving 70kph+ puts a smile on my face. Moving also spreads damage well - and I don't see the XL engine as an issue too much. So with that here is my favorite build.
Engaging as far out as you are with your weapons loadout puts that XL400 to good use, I think. Not in a ton of danger of retaliation, and 71 KPH gives you some speed to relocate, should you need. I like it! I'd maybe see about fitting an extra ton of LRM ammo, maybe by dropping a heatsink, but that's just me.
I see no sence in use an AC/2 and then just have 150 Shots... And same the LRM-racket... I`d even more use more Heatsinks and a Standard Engine and Fire Lasers as Often as Possible... hear: