I just went through this with a buddy. Luckily it's easy. Remove your cables and stuff and pull the top portion of the pole off. Then slip your tubes out from the bottom. Start with 2 inches off the pole and re assemble. You have a little wiggle room at the top and bottom to gain an inch back if you don't like it. Slowly take it down till you like your rider position. You can also shorten by loosening your lower bracket and sliding your tubes down. Once you find the happy spot make sure you take it apart and cut the tubes. You don't want tube sticking below the lower mount it will put stress on your steering cable. You'll know your on the right track it will start to feel better.
It changes your rider position by making you move more forward physically to drop the nose and when you ride in the footholds I personally notice myself pulling the nose of the ski twords me thus raising the nose. Hope that helps. If you screw up hit up
@chrisgrace for new tubes they are inexpensive compared to others. I used masking tape and a cut off wheel to cut.