@fs-keith - this is far and away different than a seamless 8x80. This is 3 times as big. The finished weight will be very dangerous - with a tag line and one end supported one could maneuver it some but not easily. A full perimeter clamping frame distributes the load much more even than single stress points. A 27x200 is in a totally different league than an 8x80. You will need building engineers involved to sign off on the loading on the wall, a safety engineer, someone looking close at wind on the day of install, etc.
We have looked at massive banner installs. You contract a professional rigging firm for this sort of installation. 99% of sign shops have no business attempting this install in house.