For my recent IST/SIN flight the bulkhead seats opened up a few hours before T-80, and I was able to get 19A via SQ chat bot.

About the seat:
* Definietly worth it from a sleeping perspective, but unless you are under about 5'8" you still need to use the cubbly hole if you want to stretch out fully.
* If you sleep in a foetal position then the seat is perfect.
* Given the width of the seat there is a lot more sleeping space than with other narrower lie-flat seats.
* The bench at the front makes a great ottman for putting your feet on when in a seating position.
* There was a bit of noise from the galley, but the main distraction was that the crew were constantly taking things out of the stowage area right in front of 19A. This didn't seem to be the case with the same stowage area on the other side of the cabin, so I might try 19K next time.
* Row 11 is definitely superior if you can get it as there is no galley in front.