I would run the lights 24hrs a day being as they are autos and even in flower that wouldn’t affect them and it helps with heat with your not too worried about your electric bill. I got a small amazon heater and hook it up to my inkbird in the tent and leave it set on 76 year round
I’ve also had issues with this right now at the worst possible time I just planted my seeds in the soil.
Usually I try to aim for 80 for seedling stage, I’ve been between 65-70 the last 2 days.
I’m no pro but depends on the stage.
Seedling 75-80 ( closer to 80 preferably).
Veg 75-78ish
Flower 75-78ish until late flower then I aim for 75.
During lights off / night I aim for 65-70.
Just my suggestions.
I had to buy a heater to put outside my fan pulling outside air into the tent. This works great for heat but now I can’t keep my humidity up
You’d be surprised how much autos can take, I live in the uk and my tent is in my outside brick shed, the tent has reached as low as 13C for the purple lemonade so did and didn’t phase her at all, autos are from colder climates naturally, so genetically she should be able to handle it just fine. A lot of people give autos way less credit than they deserve
This was my lemonade had about 2/3 weeks of very low temps