Oh... well since posting all-in-one science is acceptable, here is my version! I never stopped tweaking it, so it's not 'complete', but it is all
perfectly tuned for one set of packs every 2 seconds, and 30 second projects. (Everything - belts, inserters, assemblers/furnaces/plants, labs.) No inserter stack size bonus or electric energy distribution research needed, only logistics 1 (except for the obvious essential production buildings). (The blueprint strings and the structure counts are more up to date than the image.)
360 yellow belts, 109/48/17 yellow/red/blue inserters, 49 small poles, 14 underground belts, 2 splitters, 34/17/1 gray/blue/green assemblers, 15 labs, 5 chemical plants, 5 electric furnaces, 8 underground pipe, 16 pipe, 1 iron chest, 3x Productivity 1 module (optional).
Tried to use lowest tech inserters and assemblers wherever possible, and minimal power poles, to keep build and power costs down. In this design, space is lower priority than build/power/research costs, and beauty is even lower priority. (Except a few places use blue inserter instead of red, so it will fit.) I tried to keep the more expensive items on the shorter belts.
One fully saturated yellow iron belt is just barely insufficient (13.333 out of 13.75), so it has one to feed 1.5 iron/s, the other is 12.25. Total iron use is 13.75/s, copper is 9.5/s, coal 0.5/s, petroleum 1.5/s.
This string is the expanded version, with a second purple pack assembler (for Power Armor 2), extra 15 labs (for 45s and 60s projects), and filter inserters (to prevent excessive steel production).
Projects which take more than 30s:
45s: Electric energy distribution 2, Military 4, Cluster grenade, Grenade damage 2+.
60s: Automation 3, Worker robot cargo size 2+, all module 3, Rocket silo, all speed & damage 3+ (all projectiles & robots, except grenades & flamethrower).
45s-80s: Flamethrower damage 1+.
