Changing the timing can result in more power/increased amperage, or the reverse depending on the current settings and motor. Also using an incorrect timing setting will cause the ESC to run hotter, and possibly fail.

I beleive for the low pole count inrunners like Hacker 0 degrees is the correct setting, you are best to leave it alone unless your motor/esc is not working properly at the current setting.

I am told most esc's adjust timing slightly during operation to compensate for load etc., so there is no need for you to change anything for different propellors.