2) If you say X or N must be very large, does this prove that you measure torture and fun using in effect different scales, and therefore are a deontologist rather than a utilitarian?

I confess my knowledge of the subject is non-existant but everything I have seen has discussed utilitarianism as a sub-set of the broader class of teleological theories, and that not all of these would be uncomfortable with the idea of using different scales. And also that deontologists don't have scales for measuring outcomes at all.