Ah, unfortunately most of the crucial information was handed out on the community discord server, as this wasn't supposed to be quite so visible on itch yet... oops.
In short, each Brewery should be sustained by 2 barley fields (presuming they have enough room)
For clothing you need 2 flax farms, 2 retters, and 1 weaver.
For 40 houses you'll need: 4 barley farms, 1 brewery, 2 flax farms, 2 retters, 2 weavers, and enough markets that every house is covered by market range