NOTE: The sentinel CANNOT build it's own stacks of [Galvanized Chamber] or Aptitude. You need to carry a RIFLE also with [Galvanized Aptitude]+Chamber equipped and get kills to build stacks for the sentinel. If you are NOT using a rifle with those mods to maximise sentinel damage, then just swap the galvanized mods out for [Serration] and [Split Chamber].

Flexible options can go over either Themite Rounds of [Vigilante Armaments]:
[Primed Fast Hands] allows faster reload and more uptime of beams
Primed Faction mods helps min max damage against specific factions e.g. if you plan on an endurancee run
[Vile Acceleration] is flexible over [Primed Shred] if you don't own [Primed Shred]