Well, it seems that I did need a good few hours for that upper to be able to settle down on the back molar. It feels normal today. At least the position of the aligner feels normal. As for my teeth, they are quite a bit sore today. When the trays are on, the pain is minimal. I'm feeling mostly the tightness at that time. But when it's time to eat...look out! My kids thought that it was quite humorous to see me scream out loud as I took each bite of my food! When the front teeth (the only ones that will be moving) touch each other as I bite down, I feel like I am going to go though the roof! But if I remember correctly with the first tray this will go away in the next couple of days. I expected the trays to be really difficult to take off since they are so tight, but I really didn't have much trouble with them. I don't think that my speech was effected at all either, in fact it may have improved from the last set because they were starting to feel loose. I noticed that I would lisp until I bit down and made them fit tighter.
That's my experience so far with tray U 2/16 and L 2/15!