OK, I finally bit the bullet and bought some Look clipless pedals. I searched loads of threads, but couldn't find answers to these two newb questions:

How far ahead of stop sign/red light do you unclip your one foot out? couple of seconds beforehand or much farther out?

At what position in pedal stroke do you unclip on the one side? -- at 6 o'clock, 12 o'clock, etc?

Thanks