Unca Rog,
In "The DC Comics Guide to Writing Comics" (
http://www.amazon.com/dp/0823010279/?tag=imwan-20 ), Denny O'Neil cites a device used by Paul Levitz in his Legion-writing days to plan accordingly for the interleaving of sub-plots within a basic storyline.
Paul used to use a spreadsheet-like grid on paper to track a hierarchy of sub-plots ( B,C, and D) and their progression. Each sub-plot was interleaved with the main story A. As soon as plot A had come to resolution, plot B would graduate to plot A, C to B, D to C, and a new D would be introduced ... or something like that.
Did you ever use a formal planning structure like the one above when embedding sub-plot snippets into your stories?
Thank you.