Generate Documents: Formatting Suggestions?

I've been struggling with my PDF for document generation. I have created the layout in Excel, exported to PDF, used the prepare tool to create fillable fields, and imported the PDF into Smartsheet. It works, however if I have to make changes to the form layout/structure, I have to manually re-map about 1/3 of the fields each time I upload a new copy. Additionally, I have all of my text center justified, but it doesn't always end up that way on the final form, some fields are centered, some are left, and I don't know this until after I spend time re-mapping fields and generating a document.

Are there any basics that I'm missing? I've tried to name the fields in the PDF to match Smartsheet Column names, and nothing works to retain all of the pre-existing information.