While [Arquebex]' stats in the Arsenal do not increase with [Necramech Intensify] equipped, the damage shown for Guard Mode in [Voidrig]'s Abilities is increased (500 > 650 when maxed). Whether this is a UI bug or actually means the weapon does not gain damage from Ability Strength isn't clear to me, but I still use the mod also because it buffs Storm Shroud.

[Arquebex] is OVERKILL even without Necramech Intensify. This means you can put Necramech Continuity in it's slot and play around with some of these:

Necramech Efficiency vs Necramech Friction (vs Necramech Slipstream) is kind of personal preference.

Vizier Predasite (1-2 Forma) with [Iatric Mycelium] is basically passive health [Regen] (that needs a revive every now and then).

You could build your [Voidrig] even more tanky with [Necramech Redirection] and [Necramech Deflection], however this kind of interferes with [Necramech Rage] (remember, it says Damage on Health) and [Necramech Repair] should keep you going just fine with this build and maybe a [Vizier Predasite].

Activating Desecrate on [Nekros] (mod for Range+Efficiency) before transfering to your Necramech is a nice way to make sure Health and Energy Orbs keep spawning, alongside other loot. Great to combine Toroid farming and Necramech leveling.