Construction would be completed (For either) at the end of the 2nd month of winter, giving our bonus for the 3rd month.
We have 134 wood and require 160. This means 26 of whatever we gather this month (1st of Winter), will go towards its completion. So lets assume we get anywhere from 9-29 additional wood (after filling the requirements) from this months labor, And 35-55 wood for the 2nd month where we have enough to build it, and are just stockpiling. This would put us at ~44-84 wood for the 3rd month of winter, when our sawmill would be level 2.
And we'd gain (with sawmill), 38-60 wood on the new month, Putting us anywhere from 82-144 for the beginning of spring. Insufficient to build, OR start, our Windmill unless we do well on our rolls. Thus we'd need to wait an additional month at the least, 2 months at the most to start. This is time when we could be gaining additional food. Cause I'm sure we'll get more people.
Currently a 10% increase on our food would be anywhere from 10-20 additional food a month. Given our current food stocks, I say this is a stronger move, and it appears others agree.
Tell me, Are we so flush with food that we should consider other concerns? Each winter we have come close to starvation. Over the course of a new year, with no additional development via farms, or extra people we should see anywhere from ~90-180 additional food for our silo(with a better windmill,assuming no critical fails so on.). This would give us the stocks to move comfortably through winter without worrying nearly as much.