I own a 440' tower. A client needed larger guys to meet specifications and contracted a company to install the new guys. The company picked had never worked on a tower over 120' tall. Needless to say, the job was botched. Luckily, the tower survived and another company came in and corrected the work. There are a lot of companies that only have experience on 50-120 foot towers (a lot of cell tower experience). Moral of the story: If you have a tall tower, get references and pick a company that has a proven track record!