I'm glad you liked it!
The spire must have steel inside it to support it from the wind and the weight. Like any other antenna, it must be held in place securely.
Yup, I have a friend who is a construction manager and coordinates tasks, such as erecting cranes and dis-assembling them. Learned all the techniques from him
Basically, tower cranes are in a mutual relationship- one helps the other one get built, and that one helps the other one get dis-assembled. Once a tower gets topped off and is not needed anymore, one of the cranes gets lowered and dis-assembled, and parts of that crane gets lowered down with the remaining crane.