Does the Reactor Vessels upgrade require the reactors to be operational

The Question from your Title: The Magneto Boost Ratio boost the boost of the Magneto. The Magneto boost the Global Production by 2% per building and a Steamwork boosts this effect by 15%.

But the Steamwork can more!

With different Upgrade it can produce things like Manuscript. A Full list is here

Catnip fields give infinite catnip. Therefor more fields is better. At least, that is my philosophy. I have 47 fields right now, and the next costs 2057. During spring I have no farmers and +1.5 catnip. During summer and autumn I need 1 or 2 farmers, depending on the amount of catnip I have to survive winter. During winter, I have most of the time negative catnip production, but I have a buffer (that was a tip from a previous question) so that does not matter very much. My buffer is now 3500, after a warm summer.

It's not mathematical my answer, but I try to upgrade my field when my buffer is more than twice as much as the price of the new field. In that way I still can survive winter and have as least as kittens possible on the farm.