Wasnt sure what were you talk about and i accidentally found this..Manufactory on non-fresh water wheat is a very good choice, especially when it also makes a triangle with fresh water farms.
Jeeez, this is huge, and i play this game few years, and just learned about that

I mean, this make positioning of the first Manufactory really important.
Also, Manufactory can work as third Lumber Mill, which is perfect solution for ackward double forests early game (i usually play with reforestation any way
