Since I mostly DPS I usually let the Tank & Healer work out the speed runs while I just go with the flow. The reason I let them decide is because they can figure out how much they can pull/how fast they can do and I can match that.

I rarely see BIG arguments about speed runs ... if I do, it is in the Daily Main Scenario ... it is not limited to one class, but usually the more vocal speedrunner will make countless mistakes and actually waist time ... which confuses me 100%.