I found the seal sort of naturally wants to sit in one position when you're sticking it down.
I wiggled it around a bit without removing the backing from the adhesive so I could feel where it wanted to sit. I took a few pictures before taking the old seal off and this also helped me figure out where the new one was supposed to stick on.
Yes I was quite pleased with how the dash plates turned out. Getting a good finish is purely down to patience... The paint is very textured once it has dried, all of this texture has to be sanded away and then polished back up. If you put enough layers of lacquer on then it's just a case of sitting down and spending a couple of hours getting the finish right!