Not sure about auto's.I've never grown them.
In my current grow, I did use MH for the first two weeks after the flip,and it did reduce the stretch by about 1/3.
Why wait till the lights go out to take pic's? You need 12hrs with no light, not 11hrs and 55min.
I take the pic's when the lights are on...If I want I turn off the lights for a few minutes to get rid of the yellow effect it has on the pic's.