Re-jetting for a trip to CO

last summer i went on the paiute trail in utah. awesome trip. elevation ranges from about 5000 on the low to almost 12000. both my 03 ranchers seem impervious to anything including altitude. my 05 foreman always ran rich even at sea level and would become hard to start and severe power loss above 6000 ft. i rejetted with the dynajet kit and set it up according to their recommendations for 3000 ft. the atv runs perfect up to about 9500-10000 ft. but shows some power problems above that. the suzuki vinson on the utah trip was having major problems above 7000 and a brute force wouldn't start at 5000.

yeah, my buddy went last year, and his rancher did pretty good he said, just a problem with starting sometimes. My biggest concern is my 06 foreman, because I have no idea how it will act.

Any techs out there not tired of this subject? I really need some advice on how to make sure the foreman runs like a scalded ape at 10,000 feet. Is the dial a jet worth the money?