I think Trump is in enough trouble at the moment. Hillary shouldn't speak on this unless asked about it (she will be), and shouldn't need to drop any Machado-like oppo bombs unless they relate to this current scandal. This one has legs, let it continue to boil.
She needs to have answers ready for whatever Trump throws at her regarding Bill, emails, Benghazi, speeches, etc. She should otherwise spend most of her time talking policy matters, contrasted against Republican proposals, as if Donald wasn't even there.