My office was very close to the property line on one side. My neighbor had an oak tree that had grown to massive size much like yours, with limbs extending over both my building and his. He fortunately decided to cut it. He brought in 2 guys with a chain saw and long rope. I watched in amazement as these guys took that tree down from the top without use of any other equipment. When they got to the limbs over the roofs. One guy would throw a rope over the limb, then walk the rope toward the end. The other guy slid out on the limb to do the cut in such a way that all the guy on the ground had to do was give a tug on the rope at the right time, and the huge limb would curl back toward the tree, crashing to the ground with a thud that shook our building.