I work on it between cafs ff and bs. I like to have most of it cleared and swept out before I really start setting it. It's always full on both sides with bs. I like to pop as much as possible up and work on the stuff that's easy to bs with the wave or down the aisles.
It depends entirely on how much crap is under the line. It has taken me as little as 15 minutes and as long as an hour.
The answer is this....it all depends how much is on the line.