I had a really hard time hitting the landing point on jump #9. You need to go fast, but not excessively. After 2 dozen tries or so, I decided to shorten my run-up to half the length of the street. I then gunned it to the ramp in a Comet and hit the target, which is a tree btw. LOL
Well done! This is a big help to finding and executing those jumps. I have a tip for #17 which was particularly difficult for me. There's a path in the grass on the North side of the roadway which points directly to the ramp. If you're having trouble hitting the ramp at high speed, try that. Worked for me.