Most of the walks down this way you need to book individual sites which is a pain in the bum.
I would say most of the walks here are like that too, though obviously with exceptions.
Yeah, 'The Season' to hike is Winter and winter shoulder months, and it's a
very popular trail. It gets fully booked out in season.
They release the next day (6 months in advance) at midnight. I missed out (other people also staying up until midnight were faster than me) the first 2 nights I stayed up until midnight...
You can also check back regularly if you miss out, as people do occasionally cancel their permits opening up slots.