From my experience, it's an estimated guess every year at best. The best you can do is hunt an area long enough to figure out an average for that area. There will always be early and late rutters and lots of other variables to factor in. You saw your first swollen neck buck the 15th, and Monday is December 1st. Pretty close to "on schedule" for an animal without a schedule.
I was going on a hunt at a buddy's place a few years ago. He told me, "They always rut at this time!" I asked him to be sure the deer get that memo.
"I have no idea what WW-III will be fought with, but WW-IV will be fought with sticks and stones."