I feel like that train has left the station. I've been monitoring waitingfortesla.com on a frequent basis. Two or three weeks ago almost all of MYs that were being dropped into inventory had 20s. Lately, I've noticed a great deal more 19s.
I think changing wheel option may get you an earlier date based upon what vehicles are being planned for one's delivery location. (I tried switching for my configuration for one day and switched back as I decided it's too late to really make a difference. This waffling probably hurt my place in the queue
. )