The problem with Trail Crest Exit permits is that the 10-person walk-in quota has nothing to do with the day you walk in, it's only based on how many are left for the exit day. Cottonwood is the closest non-portal TH to Whitney, so you're last to the exit permit party compared to people who got exit walk-ups entering at Kearsarge and further north. Point being, even if you get in line at midnight the 10 slots for your desired day might already be long gone. (But still worth getting in line early to ensure the Cottonwood entry.)
This year the competition is certainly way lower, so maybe not a problem depending on the date.