1. Still works on a flat surface. Square surface. Round surface. Spherical surface. Every surface you can stand on. And its not a gimmick, its just mathematics, but it's okay if you don't understand, I know it can be confusing.
2. To get accurate results you need accurate instruments, to get an estimate you only need instruments. And my point was merely to show you that stars are more than a few thousand kilometers away.
3. If you must, then I will gladly accept it, I’ll pay the shipping
But I must inform you that it's very hard to measure these angles with only eyes yo observe.
4. What? No, this sums up nothing, did you watch the video?