The spelling is 'octuplet' by the way...

Study the tracks that already exist, and then make them more extreme, if you feel a need. Thing is, you are not gonna come up with a better design than the professionals, so why not simply copy the layout of a world class track. It will be better than anything you can come up with on your own, and you can of course change the surfaces, frequency of bumps and jumps etc. By the way, don't bother with the 4-5 ft jumps (rustler, what planet are you on? Steel jumps??!? They fling your buggy unpredictably??!?), you will just have your friends complaining when they destroy their buggies. Have you seen the Inferno promo video on kyosho's website? It's awesome, but there must have been some broken buggies after that event, they were going easily 20 feet in the air off 6ft crossover jumps...

There's an idea for you, actually, crossover jumps, you know, jumps where it's possible to have a midair collision with another car going over the oblique jump. See the kyosho video if you don't get what I mean...but u don't need to build 'em 6 ft tall!

Ooh, one more thing, my local track has a short (only three turns), fairly technical tarmac (asphalt) section before the straight, which is very popular, if you can get hold of some tarmac, of course...

Peace...