the top of the tophat (where it's not banked) is not as sharp as yours. also, the "dip" is not a dip at all; the track levels out from the slight incline of the launch before going into the tophat...
...as you can see here.
in terms of height, the section that crosses over the river after the tophat is a bit lower than the way you have it...
I appreciate your courage and determination on dealing with out criticism. You get a lot of it when you recreate something. As of now the tophat of yours seems to round, and needs to me a little more triangular like on the real thing.