I've written about my taper many times on SR. I tapered off a 12-16 units per day habit down to zero in three days.
It worked for me, BUT I didn't try to work a long taper with planned step-downs. I wanted to quit, I used the taper as medicine. I also knew that if I had more than two drinks, I wasn't going to stop that day and would just keep drinking. So my taper was 2 on the first day, 1 drink on the second day, and a half shot of rum on the 3rd day. It was only to keep the symptoms manageable and I didn't chug the drinks, I sipped them through the day.
3 days. If I hadn't been able to do it, well, that wasn't an option. I WAS going to do it.
To be fair, I didn't know alcohol withdrawal could be dangerous. That may have influenced me in a bad way had I known that. In my case, ignorance was bliss and it ended well - maybe against all odds, but it did.
I came to SR on day three or four of clean sobriety, I think. Forums had been helpful to me in other areas of my life.