Don overtink it mon, just pot it up when you need to and it fits in your schedule. Lights on lights off its all good as far as im concerned. cold air, with lights off would not be good for transplanting, but wud not kill ur plant. warm an cozy is best.
Think about this tho, farmers have been transplanting in the light of day for a long time. planting early in the morning especially in hot summer is best. noone shud plant out seedlings to the field at noon, so armed with that u shud be able to get it done.
if you have a 1000w hps, be concerned, if t5 do not, and all variations in between, hope this helps.