Galvanize and Noct Sect overwrite each other, no matter the potency of the barrier. When you find yourself with downtime on AST, DoT's are a great way to spend your time. Be careful spamming nukes, though, as it will chip away at your MP, and Nocturnal Sect is typically more MP intensive since you need to actively apply barriers, unlike Diurnal Sect where you fire and forget HoT's. You can play with both Sects and determine your preference, but don't neglect Diurnal Sect during your leveling process. It's HoT's synergize well with buff extending CD's like Time Dilation and Celestial Opposition, which have very little to no benefit when used with Nocturnal Sect's barriers.