If you do use varnish it should be clear, otherwise it looks awful after a year or so. Wax is higher maintenance, but does look nice. Until it gradually becomes a mixture of wax and filth, like old school floors.
As a teacher, i have seen the school assembly hall treated with an oily wax called "Bournseal" - This is done every year with the buffing machines usually in the summer hols.
Call into your nearest school, make friend with the site manager/caretaker and they may even give you some in a pot!