First: If you want an # Order, the number must be first (alpha sorted) and the same length (characters) (and don't get the overall title too long )
05.5-Foo on a Stick
The Metadata plugboard is what you want because Kindles use metadata, not file names.
Code:
{series_index:0>5.2f|| - }{title}
Into {title}
I left out the Series Name But you could put that APPENDED to {authors}
Code:
{authors) _{series}
Authors is a valid field, so I kept all those together , then append the series name