How do I go about flipping my light cycle 180 degrees?

Howdy.

Since the weather is starting to warm up, I currently have two plants, about another 30 days from finishing in flower. Initially I was just going to flip this to when the lights are on at night instead of the day to help keep the box cooler. I would do this AFTER these two plants finish on their current schedule.

Would I have to do it incrementally, or would it be better to say just give them the double dark cycle, then back to the NEW lights-on schedule?

Thanks!

double dark

have to agree, extra dark period rather than extra 12 hrs of light.