A thing to keep in mind: you can't be sub20 if it takes you 15 seconds to do F2L.
If you reach last layer at 17-18 seconds, knowing WV, ZBLL or COLL won't help at all.
As PetrusQuber said, practicing should do the trick: it'll help you gain back muscle memory and will make recognising patterns easier
If you reach last layer at 17-18 seconds, knowing WV, ZBLL or COLL won't help at all.
As PetrusQuber said, practicing should do the trick: it'll help you gain back muscle memory and will make recognising patterns easier