I have the red/infrared light bulbs here for the RFs (one likes it on all day and the other likes it only at night)
If you have a tank heater for your RESs then the water should be at around the 78 degree mark all of the time...so to me the best thing would be a basking day light bulb and a uvb for the daytime....
When I turn the day lights off for the turtles they turn in for the night...one sleeps while laying against the floating dock with one little footsie touching and the other likes to sleep half in the water and half laid on the dock....and our house during the winter at night is usually 68 ish.
Just my gig here and what I think...wait round and see what the others think and offer up...the more the merrier...