Here are my tips against Carl
First thing's first, if you're facing a good Carl, don't expect him to just sit back behind Nirvana cause that wouldn't be too smart. As most of you probably know already, when he spins around you, you can grab him out of that, so I suggest using Gigantic Tager to punish him. Now then, Carl himself, though weak, is fast or at least, faster than Tager (But so is almost everyone else).
Mike Z. gave a good tip, finish him as fast as possible, however, the big flaw with this tip is that a good Carl isn't going to finish fast.
A smart Carl player will try to rush you down and pressure you with his combos, however, he can't rely on this way too much. If you distance yourself from Carl and get far enough from Nirvana, a good Carl will attempt to rush you down, BE ON GUARD! Try to hit him before he can reach you, this is common sense of course, however, it still needs to be reinforced and understood. Now then, one of the biggest mistakes is getting in between Carl and Nirvana, an obvious mistake. Remember as well that Tager may not be a fast character, but he can still work fast.
Carl CAN'T use Nirvana if he's being attacked at and blocking, pressure him a bit and trick him into getting grabbed because of this. Even if he does try to use Nirvana within a second, remember, Nirvana's hands are accounted for as projectiles, however, Sledge isn't always the smartest thing to do because Carl could be playing you just to grab. Pay close attention and think about when you're going to use Tager's projectile as well, because as Mike mentioned, Nirvana can get in the way. Try not to concentrate so much on attacking Nirvana and putting her in commission as much as, trying to keep Carl from using her and tricking him. Nirvana isn't the one you're trying to kill, Carl is. One of the most annoying things about Nirvana is that because Tager's jump is so crappy, he has a harder time jumping over Nirvana, so super jump over her. Also, a good player will know when to rush you down, a good Carl will know to do so as well, so don't expect a good Carl to straight up rush you down.