I think people have done the Whitney trail much faster than 2 hours and 50 minutes. I think whatever time it took to do the Vivian Creek Trail you could double that time and it would be a good indicator of how long it will take someone to do the Mt. Whitney Trail. I did Mt. Whitney that year in 5 Hours and 30 minutes with two other people. Then we ran down in 3 hours and 30 minutes. Would that have been a good indicator for what your times were?