I consider there to be 3 plans for TFs: normal, kill all, and speed run. Speed run is skip as much as possible. Race past the enemy to get to the mission goal. If you want to do that you should advertise it, as it is very different than playing through.
I don't consider +0 a speed run. The difficulty setting really depends on your level and if people are playing on easy mode with IO sets and incarnate powers. If you are playing the base game I assume +0 up to 20, +1 in the 20's, +2 in the 30's, and +3 in the 30's to be "normal" difficulty at this point. Even without IO sets and incarnate powers, +0 is easy in the 30's.