Ability strength mods affect the percentage of damage absorbed by Ballistic Battery and its maximum stored damage, the damage bonus of Shooting Gallery, the damage reduction of Shatter Shield and the damage bonus of Peacemaker. The damage of Peacemaker can also be increased by modding Mesa’s Regulator pistols. Ability Range mods affect the stun range of Shooting Gallery. They also affect the bullet reflection range of Shatter Shield. Ability Duration mods affect the duration of Shooting Gallery, Shatter Shield and the energy drain of Peacemaker.
So, all things considered, here are some builds you may want to try on your Mesa: