Ok, I finished it. See what you think or anyone else who wants to try it...
I think my quickest time was 49secs, just so you can compare it to the real track...
I've attached some screenshots to look at. I didn't use barriers for all the track, I tried it that way and it was way to tight. Hope this works...
I can try another way if this doesn't work. I did it there so I wouldn't have to move the start so that the layout can be used for a race, but I'm not sure how it will work for racing, we'll see.