I'm inclined to believe Cere takes both. Cal seemed extremely impressed when he witnessed Cere fighting through the purge troopers, implying a gap of ability between the two. And she was able to slow Vader with the Force, both when she was tapping into the dark side, and when she utilized the light. Cal, meanwhile, was absolutely no threat whatsoever to Vader. Granted, Cal has many more feats than Cere, especially against other Force users. But lack of feats shouldn't be a reason to put Cal above Cere.