Hi @Rodread,
A brief history to lead towards an inflatable version with helium or hydrogen (which may be possible because everything spins at the same time, reducing the risk of static electricity by contact).
The catenary sag effect was very visible on Serpentine because of its weight, and not visible on three-rotor-based Daisy. But one can suppose that for very long lengths, it could occur.
An analogous solution could perhaps be possible with the currently discussed version with inflatable ballutes, which would generate aerostatic lift at each rotor, capable of mitigating or eliminating the catenary sag effect as well as (to a lesser extent, or else on a large scale with volumineous ballutes) the bending forces of the wind. Thus, the lifter kite located at the top would have less work.
It remains to be seen whether the whole system would self-regulate with different winds for each of the rotors. Perhaps this could help to start knowing it. And also the drag of the ballutes should be reasonable (although that remains to be seen), knowing that the maximum speed would be at the tip of the blades.