(right click "open image in new window" for larger) The idea is simple. I feed sets of resources off my main bus to this line of assemblers in parallel rows. Some mixed, some not. Belts start 3 spaces away from assembler line and I leave 1 space between belts. The order is not so important but you may find variations that are easier to split.
Belt Makeup
Then i set assemblers, with a space between each, in groups based on feel and feed order (Inserter->Fast Inserter->Stack Inserter). Breaking resources off this brach bus is just a matter of of using a splitter and underground belt for each resource. Passing items between assemblers is as easy as an inserter between. Generally you want to limit your output chests to something appropriate. For me, Train tracks I never limit but splitters and underground belt may be limited to 100, etc...
Examples
Poles
Train Things
This is obviously a fairly early game example. Next steps are to change chests to passive providers. Add Requester chests to Belt/Inserters for trash cleanup and recylcing. Some of the belt items can be supplemented with additional belts (red circuits are obviously missing in my example. I leave room to add this later) or you can fill this need with requester chests as you go. This typically remains a permanent structure in my base though very late I may supplement production of megabase items like belts and inserters.As an added bonus the Click and Drag function of .15 means I can walk down the hallway holding control and just grab everything!
I pair this setup with my FARL train pretty early on. As soon as I get requester chests i set them up to refill my train with all manner of items that I need to build remote factories. Its really great if I am off building a base somewhere and I go "CRAP I didn't bring enough splitters". I just sent the train home while I continue and then request it back. Its like
I will attempt to add a late game Blueprint later but for now I hope you enjoy the idea.