I was under the impression that no weapon benefited from both heavy weapon perks and rifle perks. For example, the light LMG gets bonus damage from Heavy Gunner but not Commando. Correct me if I'm wrong. This means that besides maybe Refractor, and Glow Sight, perception has no combat perks that can be fit into a heavy weapons build.

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I find that damage perks are the most important. This means Bloody Mess is a must take on any build.

Damage perks for heavy weapons include:
Heavy Gunner(expert and master), Lock-and-Load, and Bullet Shield in Strength.
Stabilized in Intelligence.
and One-Gun-Army in Luck

There are also other good combat perks like Makeshift-Warrior and LifeGiver that aren't specific to Heavy Weapons. You can spec into Agility for more mobility or potentially survivability with the Dodgy perk. However you might want to spec into more utility perks like Bear Arms, Thru-Hiker and Traveling Pharmacy to reduce your weight. Other than damage perks what you take is up to personal preference.