How do I smooth lighting across verticies on top of eachother?

If I have vertices on top of each other to seal my model shut, how can I make the lighting basically pretend they are doubles so it smooths the lighting across? So it looks like there is no opening

I’m not entirely sure what do you mean, but as a rule of thumbs - you do not want verticles on top of each other. Make the geometry clean, instead of thinking how to patch up a messy one.