Hrt will likely stop the growth, and has in some cases caused some to lose a few inches.
As for height changes during the day, so it at the same time each day.
When you wake up, your skeleton has time to relax and stretch. Throughout the day you beat it down, and you shrink a bit. am not sure if it is all fluid or a bit of cartilage, but something compresses, resting/laying down allows it to relax again,