You would like to use the character that is supposed to produce the most damage so that you will be able to advance to the other stages of the game. A DPS tracer would have the ability to check the different DPS of the characters, but you have to remember that the current conditions will also affect the type of strength and power that the characters will exhibit.
You need to know the damage that will be done in the entire clip, the time that it will take for the clip to be reloaded, and the reload time. Will all of these details, you will be able to see that Tracer is stronger as compared to Genji.