Auto and fem the same run?

I did this on one of my projects. I vegged out the photoperiod extra long and then switched to 12/12 when the autos were finishing up in week 12 I think. granted my autos flowered in the 4th or 5th week so it worked out well but if they don't go into flower til the 7th or 8th like some people that could be a bigger issues. Autos will grow on 12/12, just not as well as 18/6 unless the DLI is met, so you could try lowing the lights to increase its DLI or adding in more lights. The closer the light is to the plant the higher its strength and less lighting it needs but this is all limited by the wattage of the light. Its easier to just add more lights if they can fit. but not so much they burn from light stress. So the other question is do you have time to wait? If yes, let it veg longer, if not just switch to 12/12 when the photoperiod plant is ready and go from there, the autos may not be as big as they could be, but you will still get a yield out of them. Best Of Luck!