Is GT4 still available?

I used Track Precision. It does support Thunderhill East but not the new, short West track. I made a custom track, where I defined just the start/finish line using the Map feature of the app. I tried using satellite view but Thunderhill West is so new that the satellite map still just showed dirt! However Apple's Map app does show the track, so I was able to confirm I was putting the start/finish in the right place.

Here's a video I made of how to set up Track Precision: