I have a 2004 YZ250 2-stroke and only ride trails in the Colorado mountains. I typically ride at an elevation of 9,000 to 11,000 feet. Because of the altitude the bike probably has approximately 25% less horsepower than at sea level. The bike is jetted for my elevation. Should I get a 9oz or 11oz flywheel weight. I'm afraid to get the 13oz because the bike has less power at my altitude. My goal is to make the bike easier to ride on tighter single track trails.