Since some changes were made to the capacity of the storage buildings available on planets I decided to try a different layout on my extraction planet.
This new layout means I now have a constant storage capacity for both factory input and output rather than an ever decreasing capacity for input depending on how much output was stored. It also means I can wait twice as long before doing an export run to my planets - with the old set up I would starting thinking about collection when the launchpad got to about 50% capacity.
I envision a similar layout for factory planets. All input materials will be imported and moved to the storage facility where they will go through the same pipeline and be ready to collect from the lauchpad. The only difference should be in the number of factories, although I may require more than one storage building. More about that once I've tried it.