1000 spoilers could be out anywhere from Christmas day to new year's. Shit changes every year.
Because every year schedule is different.
This year spoiler day comes around 29th. Online chapter would be around 1st Jan and official around 4th Jan.
That's the schedule.
Early leaks can't be predicted.. it's not something concrete because it's risky.
If you get one good but if you don't then you have your schedule.
All I am saying is don't rely on early leaks.
However, rest assured that 1000th spoiler would be available before 2020 ends