I did not write that article, but it's a good one so I have it linked in my signature.particularly the 'how much space do they need' one. In that you wrote
Yes, you can have a smaller coop(less floor space) in mild temps with a wind and rain protected covered run, BUT you still need to have room for them to navigate roosts feeders nests etc.
Roost length can be one serious limiter in a smaller coop.
12" of roost length per bird is a good rule of thumb,
BUT that can depend on how high roosts are and how much landing area is needed to get down from roosts without crashing into something.
Crowding on roosts can cause much stress and even injury....the RoostTimeRumble is usually a pretty combative time of the day. They might squish into less space to actually sleep, but they need more space to fly up and jostle for position.
Another detriment to a smaller coop is adding new birds, which almost everyone does eventually due to wanting more birds or just replacing with fresh layers or due to losses from other issues. Integrating new birds takes 'extra' separate but adjacent space...so keep that in mind too.