It's very flight-specific and variable. I regularly book last minute as a 100K and can usually get PC window/aisle. Sometimes all I can get is an exit row and if I can't at least make PC or rear exit aisle/window will find another flight.. It's rare to have no availability in PC but pretty common for the only availability to be middle seats. What route are you looking at and I might be able to give you more accurate info from my experiences (+/- 20 west coast to/from Hawaii flights in 2022)?