Fedora Master, I finally salvaged a Warhammer, since I'm pretty starved for heavies atm I started thinkering with it. Here's how I roll:
Double AC2 with 600 rounds is a versatile and decently powerful ranged option. Its biggest advantage is, it forces you to learn how to aim at those pesky, far away crawlers, it's also the main AA option for the build, you need to play both angle and elevation to shot down Vtols, it's pretty fun.
Quad chem laser is a less impressive alpha strike but it's still unpleasant to receive and you can sustain the four of them cycled while remaining neutral or slighly cooling of with 3 HS. As for weapon groups, left click is cycled double AC2 for distant (or close) sniping, you have 600 rnds, be trigger happy and you won't regret it. Right click is double AC2 (uncycled) + SRM6 for mid-close range alpha strikes, beware because the SRM6 is a deceptively hot weapon. Group 3 is your cycled chem lasers, when alpha-striking you either only use balistc and missiles, or press both buttons for true alpha.
Don't fire your lasers uncycled in that case, heat buildup is not worth it. You have maxed out armor on a 61Km/h chassis, you can definitely endure more than they can, especially if you aim for weakspots.
You could remove one ton of armor or one HS (bad idea) to either get an Artemis or install something in those small energy slots, some SB small lasers or high powered dildoes, your choice. During my tests the average engagement range didn't favour any of those but ymmv.
edit:
Agesilaus, yes, I'm serious! Want me to show some post battle results? It's performing pretty well.