You are correct, but only because you didn't make it apparently clear that your running it on a Verticle Dropout frame... Does the Eno even have threading for a freewheel on both sides? I haven't had the opportunity to run an Eno yet but I am on the hunt for one. I'd think that you should be able to get away with a 4 tooth difference, but there is no knowing with certainty until you try it out.

How much space does the Eno hub give you in a circumference?