Resting vs loaded will depend on the load. Running my furnace vs the microwave produce very different loaded voltages. I would not worry too much about it. Let the batteries work for you. Don't work so hard thinking about batteries to get 7 seasons instead of 6 from them.
I mostly check mine first thing in the morning to see how bad it is and again in the evening to see if I will make the night. Adjust accordingly. Don't wait for the last 20 minutes before quiet hours to run the generator. Not going to do much.
If you wake up to 10.7 volts you could do a little more charging the night before but I would not turn off my furnace for it. And likewise if you are still at 12.3+ and it is convenient to charge go ahead and do it.
If you run them hard be sure to give them 3 to 10+ days of plugged in recovery time upon return.
