A few days ago I tested all the workshops in Charas for my own use. I'd like to contribute to the amazing work you've done, here are their incomes:
Brewery - 70
Velvet Weavery - 0
Linen Weavery - 0
Wine Press - 0
Pottery - 150
Olive Press - 45
Wool Weavery - 130
Tannery - 200
Wood Workshop - 25
Smithy - 30
Silversmith - 0
The zeroes did generate like 10 income for a time but in the end they didn't generate any income for a long time. I tested the workshops each starting at about 30 days into the game.
Brewery - 70
Velvet Weavery - 0
Linen Weavery - 0
Wine Press - 0
Pottery - 150
Olive Press - 45
Wool Weavery - 130
Tannery - 200
Wood Workshop - 25
Smithy - 30
Silversmith - 0
The zeroes did generate like 10 income for a time but in the end they didn't generate any income for a long time. I tested the workshops each starting at about 30 days into the game.