Warm up usually takes from the time I start the bike, do my jacket up, put helmet on, glasses on, gloves on and sitting on bike, may take a little extra time if partner comes with me. So anything from a minute to two minutes. As soon as one or both of us are on, chokes off, in gear and away.
This time of the year I will use the choke but in warmer weather I rarely do. Idle speed with choke on equates to about 60 kph so keeping revs low for a few minutes won't hurt.
As bikes go 1100/1300's are relatively quiet anyway and as for before sunrise, I don't even go there. I have no trouble going to bed in the middle of the night but getting out of bed before sunrise is just not on.