First of all there is no formation to beat Classic or any formation all the time.
Yes sometimes formations works to beat Classic like ND and 4-5-1V, Only ST`s are not the only you should mark them, Mostly Managers play Classic focus on flanks So if you use 4-5-1V against Classic your DL&DR defend the flanks (His ML/MR) DC`s cover ST`s and DMC defend against MC`s and when you attack DMC go further to attack.
I am not fan of changing formation all the time.