The damage increase isn't what matters; it's the absurd meter gain. Dorm with meter is far 2LMS, 1D:2C (TK this right after the launcher or it won't combo), 2MS, j.MMHS, OTG pillar xx super builds 1.25 bars. This is huge for Dormammu because he's pretty shit at building meter on his own without some kind of assist that lets him mix you up a bit (Sent drones, plasma beam). Even then, they aren't abusable (especially if you use Sent). The spell itself builds half a bar if most of the meteors hit, but I don't advise using spells outside of combos because you're wasting the time you spent building them up. D3 is good because it limits the opponents' options; especially if they have a projectile. You can beat them with it on reaction and combo into dark hole xx super. Like 1D:2C, it can also extend combos for extra damage and meter. The rest aren't very useful in my opinion. Go for 1D:2C if you plan on rushing down, and D3 if you like limiting ranged options. Of course, you don't need them in every match-up and it's up to personal preference, but that's the general rule for me when I play him. The simple way to buy time for spell storing is to use the ball super on an incoming character. You can also get free spells after an airborne enemy blocks a pillar, instead of going for chip with another (which is a better idea if they're not about to die, in my opinion). Experiment and do what works for you.