I see the 3x ERLL 1x GAUSS build more and more, after the new GH. I think the 3D can load this setup successfully, laser duration quirk will help this setup as well. More ammo : Can mount XL290 but the speed gained is so few that I'd prefer more shield arms, given the XL, for this build, anyway :
A bit slower, and replacing one ERLL with 2x ML. But fullish arms, STD engine, CASE. Or even slower but keeps the 3x ERLL.