Major muscle groups are worked out only once a week, but can abdominal muscles be worked out twice a week? Aaron Marino of alpha m. addresses this question.
Though his experience, major muscle groups are worked once a week so you are basically ‘beating the crap’ out of it and needs a week to recuperate. With the ab workouts, the muscles aren’t tearing down muscle tissue the same way. The abs are an exception to the rule because you are not using heavy weight and not tearing them down. Space them out two days in-between workouts. In regard to symmetry, do not use different weights. Lack of symmetry does correct itself.
