Okay, here's what I got for Standard Tactics
While it's quite vague how he fights due to the lack of information and a boss fight that doesn't abuse overpowered abilities to decrease difficulty, Gunvolt's standard approach to combat can be determined based on the games' basic combat flow and mechanics, as well as his boss fight in Azure Striker Gunvolt 2
Since there isn't much information to go off of, it's quite safe to assume that Gunvolt utilizes Skill is best fit for the job, healing when he is at lower health, or using Crashbolt to attack enemies too high for him.
Gunvolt's fighting style revolves around his electrical capabilities. His preferred tactic, employed in his boss fight and appearance in OVA, is to Tag with his firearm's Bolts at a distance or while moving acrobatically before shocking them immediately afterwards with the Flashfield. While he seems to wait until three Tags are landed, Gunvolt has shown to activate his Flashfield before then as seen in the OVA. Regardless of when he performs it, if he happens to be Overheated by the time he lands his desired amount of tags, he will utilize the skill Split Second to give him the chance to attack; he can do this as many times as he wants. After he lands his Flashfield, he immediately Recharges to refill his EP, before repeating the process.
In close quarters combat, Gunvolt utilizes Dragonsphere to deal lasting damage, possibly giving the incentive for his opponent to back away. While trained in karate, backed with his appearance in Blade Strangers, Gunvolt's style still heavily revolves around ranged combat.
Should he decide to finish his opponent off, or if he is in a pinch, Gunvolt utilizes an Offensive Skill. He prefers Luxcaliber over his other attacks, shown in his Boss Battle, OVA, and the Copen Chapter Drama CD
If he recognizes that he needs to finish a fight fast, such as if there is a hostage involved, Gunvolt dashes into range utilizes Astrasphere.
Shown thrice that he typically uses brute force to get out of holds, Iron Maidens, Ice Traps, Petrification. Though, this sometimes doesn't work as with Carrera, Eden Drones, and Desna
Gunvolt also seems to know when he is outmatched, and decides to retreat if given the chance as shown against Copen in the Frozen City
Once Anthem is activated, Gunvolt's entire fighting style is switched to unleashing massively attacks repeatedly. Gunvolt exclusively utilizes Luxcaliber Shoot, and then Astrasphere Mandala and Voltaic Chains Thunder later on. When he's pressed, he activates Septimal Surge to double his damage output for all three of these devastating attacks. Gunvolt typically air dashes and air hops to get into better position for these attacks, especially Astrasphere Mandala.
On the defensive side, Gunvolt showings don't have much to go off of. As shown in the OVA, he doesn't completely rely on Prevasion, as he makes an active effort to dodge and weave away from attacks or colliding withe enemies, even while Prevasion is actively protecting him. He prefers to dodge enemy attacks as seen in the OVA, but it's likely that he determines whether guarding with his Flashfield or dodge is more suitable, such as dodging Greed Snatcher bullets. Throughout both games, he mostly ignores the existence of Prevasion as evidenced by midstage dialogue, instead either being told to use his Flashfield to block enemy attacks, commenting that he could disarm Gibril's blood traps with his Flashfield, or being told to watch out for spike traps when Prevasion can easily negate the damage.
