Elevation limits??

I'm working on a track, for a newly rebuilt basement. It will be 100% sport track, 2 lane.....it will be a permanant setup, fully landscaped. I'm wondering if there are any limits to the elevation changes?? What would be the maximum Rise/Run rates?? the space is baisicly an L shape, 20 feet X 12 feet on the long sides, and 5.5 feet wide...I'm thinking that I would like an elevation change of 2-3 feet over the length of the track (from lowest point to highest) Ideally I would like the finished product to look like it was cut out of the side of a mountain, as I have decided to call it "The Granite Ridge Circuit"

I've seen many pics of landscaped and "elevated" tracks, but it always seems as though it is just a few inches of elevation....I'm wondering if there is a reason behind this?? is the flexibility of the track a limiting factor?? Any input is appreciated