I went a bit further back when I got my EZReader that only use a file list
@Chaley whipped this one up (I later did a minor tweak to handle Hierarchical series)
Code:
# Calibre Send to Device 11/2013
program:test(field('series'),strcat(
substr(field('series'), 0, 1),template("-series/{series:subitems(0,1)||/}{series:subitems(1,2)||/}{series_index:0>5.2s}-{title}_{authors}")
),template("00noseries/{author_sort[0]}_authors/{authors}/{title}-{authors}}")
)