Search for single nights in either North Pines or Lower Pines.
You have missed the initial reservation window so you will need to hunt and pick for anything. You may need to check daily. Best bet is mid week.
A couple years ago I was in four different sites on four consecutive nights.
Got to be a late morning routine to swap spots before heading out for the day to explore. Don't get picky, any site you fit will be fine. There are no bad campsites in Yosemite.