What location on earth experiences the most change the number of daylight hours?

The American Southwest and northeastern Africa are the two sunniest regions of the world, with the U.S. city of Yuma, Arizona, taking the crown as the sunniest place on Earth. Yuma, located where the state borders both California and Mexico, receives more than 4,000 sunlight hours per year and averages 11 sunny hours per day over the course of the year. Following closely behind Yuma is another U.S. city -- Phoenix -- which receives an average of 3,872 sunlight hours a year. The third sunniest spot on Earth is Aswan, Egypt, which has an average of 3,863 sunlight hours every year and averages 10.6 sunny hours per day.

It really doesn't matter for any of the questions that you've listed.