I tried kombucha once with an airlock, and it suffocated, but I've also had batches ruined by little flies that infiltrated the cheesecloth. I would prefer to keep it as closed as possible, but I don't want to suffocate it. Will I be okay with just a covered space over the airlock hole, or does it need a bigger hole to breathe through?
Kombucha, unlike kefir needs plenty of oxygen to do well. I wold not recommend air locks with kombucha. A properly secured cloth lid, paper towl or handkerchief should be enough to keep the fruit flies out.