Not sure anyone here will "know" where he was born, we can only go by what he said in the censuses, and what Ephraims were baptised in that area at that time, the same as you have done.
The next step will be to try and trace all three Ephraims forward. For example if you find one dies in infancy, that one can be ruled out. If any of the others survived to census era, then you may see if there are any clues to narrow down which one of the baptisms relates to them, thus ruling that one out from being 'yours'.