30!!!???The real case depends on too many factors... please try to refine your problem.
You know that also for a good computer to find the better /shortest way to visit 30 customer will be a hard job... (try to computate 30!)
1) You probably forgot that the shortest distance betweens 2 points on the sphere IS NOT A LINE, but a curve called "great-circle distance".In their two regards, minimization and maximization of length occur in space and spacetime, respectively, as a general rule for straight lines. The TSP might be recognized as either a minimization or, correlatively, a maximization of a path.
In Euclidian space, the shortest distance between two points is a straight line. In spacetime, however, the longest distance between two points is a straight line. With the TSP, maybe they can be considered two sides of the same coin. One side seems to work in spherical geometry on our globe.
What creates this seeming shortest/longest anomaly is that time appears in Pythagorean special or general relativistic spacetime reasoning as an "imaginary" rather than "real" magnitude. This infers curved space, as opposed to flat Euclidean space. However, traveling between two points on the Earth's surface maximizes their relative distance compared to tunneling directly though the Earth.