Type on a path - text to large when it's not

I'm trying to create an a design using text that arches, but the text is never centred and can never be large enough to fill the path I've designated. In order to fit all the text, I have to minimize the size, but as you can see, there is still lots of room on the path, so I don't understand why making it a bit bigger in turns makes the words dissapear and I get an overset text error. Even with large text, it seems to me there should be room for the "to a" used in my example. How can I make the text go the whole way, while keeping it a decent size? 

I think part of the issue is there is a lot of lost space as the text does not start at the beginning of the path, how can I fix this issue? I am not using a circle since I want the rounded rectangle look, so using the direct selection tool to adjust the angle of it so it appears centered/alinged does not work for this project.