1. Check your hard landscape;
2. Check your all day events;
3. Check your tasks for what you can do when you have a *free* slot.
So that includes your Closed Lists concept as it doesn't say if you should construct your list it in the moment or the first thing in the morning
When there's no real priority then it doesn't matter where to start on the list and when you have real priority coming your way (gut feeling as usual) then you skip your lists and do ad hoc!