Only problem with Flare is you're not always going to have SC+Flare available when Bulb spawns in middle. You're also not always going to be in Astral Fire when Bulb spawns. If you're in Umbral Ice, a swiftcast Flare is going to be useless.
I'm going to assume you mean Convert when you say "CD" there since you refer to double flare, that'll be available even less often than simply SC+Flare.
As for tab targeting, just make sure you pay attention to what bulb it tabs to as sometimes it decides to be a pain and tab to the wrong bulb, but yes, tab targeting is the best option.