You definately need to ride some sleds. Track legnth really isnt going to be a big issue between 153 and 162. That is only 4 inches on the snow. I would concentrate more on the chassis that serves your needs best. If jumping is really what you want to do, you can go Ski Doo and get a 146x16 track which gives more floatation for the legnth and Doo's are excellent jumpers, very well balanced for it. Also depends on where you live and what kind of snow/terrain you ride. If you are in the Pac NW maybe a shorter track is better for the heavier snow. In CO where the snow is usually very light and dry I like a looooong track. Turning isn't and issue when the snow is light and deep.
It is a compromise, there is no silver bullet. The good news is, they are all FUN.