What I'd be asking myself, if I were creating such a world, is a flat world a necessary attribute for the story? Consider Larry Nivens Ring World, Nivens created a lot of science behind the reasons, the engineering, of why a ring world is a necessary attribute to his fictional location. Does the gods of your world need it to be flat?
So if there is no 'hard reason', rather being a preference one way or the other, I'd keep to the real world, and suggest you do a globe. If you do have a good reason for needing a flat world, then do that. Don't make it flat unless there's a good reason to do so. I have no personal preference one way or the other for you - for me, I'd make it a globe.