So I have a couple of questions I want to ask gunners.
Why do you use valiance?
Pretty early on, it is drummed into people's heads that normal damage is suboptimal. Yet there is 5* gunners with valiance, and they actually use it. Why? Is it for utility? Is it for lockdown only?
Do gunners use side-arms?
Bombers generally use a sword for knockback or a gun, and swordsmen generally carry a gun (polaris). Do gunners use a sidearms? What would they be? I hardly ever meet gunners in the clockworks, so I have no clue.
A Shivermist Buster is of some use for a gunner. Mostly in Danger Missions. Usual loadout is just two guns though. If you don't mind non-standard specialized equipment, a Cutter of some sort will save you more than once from Greaver swarms. Guns are not very efficient at keeping you safe from those things whereas a quick blade strike will reliably keep them from biting your face off. This applies especially if you aren't prepared for the attack and get swarmed. You're done for if all you have is a Magnus at that point.