What were your rpms when you were able to get on plane? I would find a prop in a 23 or 21 pitch and see what you can do with that. If you know any of the guys in the Nevada BASS Nation, they should point you in the right direction, theres also some guys in the Colorado Nation running Cats. If you havent faced the high altitude issues before, youre about to join the club. I would really try to borrow a 23 Tempest or BravoXS four blade and try those. You arent going to be running a 25 pitch prop at 6100 feet.