Well, you can actually get - depending on tree size, number of taps per tree, tree health, previous years' growing conditions, etc. - from 10-12 gallons of sap per tap per season. The number of taps in a tree depends upon the tree size and tree health; don't kill the goose that lays the golden egg. Take less sap from more trees and they'll all be better for it. Locally, some of the producers get a bit over a gallon of syrup per tree per season when the flow is good and that's from big trees, but not all trees fit that bill. That's about 40 gallons of sap per tree! And, we're talking sugar maples.
As for making syrup, there are a lot of "formulas" etc,; for instance, there's "The Rule of 86," which bases the amount of sap needed to make 1-gallon of syrup by the fact that there's 86.somemthing% solids in industry-grade syrup, others that just go by the seat of their pants, and so on. But generally, anywhere from 32-43 gallons of sap to make 1-gallon of syrup. BUT -- since you only need to get it to LESS than syrup, use your hydrometer to tell you when it's where you want it to be.
Anyways, as with anything else there's going to be tons of stuff out there with a simple Google search. It's not that complicated. You'll enjoy it!
EDIT: Yooper, don't you mean a gallon of syrup per big tree? I know that even from some 12" diameter trees, I've gotten more than 11 gallons of sap in a season. The BIG trees just seem to be peeing sap on warm days following cold nights, lol!