Why specifically couples, are you looking for the high/low preference range between the pair?
We open our windows as soon as the sun drops, leave them open all night and close back up and close blinds around 10am when we start to get hit with sun. House will stay under low 70s until 1ish. I've started turning on the AC at our target temp which is 74 rather than waiting until it's hotter and having the AC have to work harder to get the temp back down.
Lately we've been trying to "pre-cool" a little in the mornings so that the house can slowly heat up during the day without the AC going full blast all afternoon. It's working okay, but not perfectly. We still struggle to keep the upstairs bedrooms cool enough (76 or below) without overcooling the downstairs (72). The AC is usually set somewhere in the middle (74ish).
When sleeping, normally 68. During the day it can vary a little depending on what the weather outside is doing and if we’ve just come inside from extra hot or cold weather. We’ve got a mini split heat pump though, so typically we’re only running the inverter in whatever room(s) we’re in rather than keeping all the units on at a consistent temp.
My upstairs used to run about ten degrees hotter until I installed a booster fan in the duct to pull cool basement air up there. I know they're generally ill-advised for most scenarios, but it works incredibly well for me in summer since it would have been a very expensive proposition to upsize the vent, install a return, or put in a mini-split.