I *think* they load a handful of "web special" seats @ 330 days as a default, and those are priced pretty nicely. Once those are gone, it goes dynamic and the cost starts flowing with their algorithms.
I say this after just booking some LAX-SCL tickets for Nov 2023, booking travel at about 320-ish days out..... I looked back at the same flights a few days after booking ours and saw the miles cost had increased by about 50K, up from the "web special" pricing we had locked in.
Just 1 DP for that particular destination, but I think keeping a close eye on the availability as they open up @ 330 days is your best bet.
Book something at a price you are good with, and then check every week to see if things have gotten cheaper - you can always cancel and re-book if they miraculously become a better deal.