for each blade an element of anhedral bank helps to maintain tension across the whole x structure
(outer tip closer to ground than centre)
I’m kinda sure - This anhedral also has the effect of slowing down the cross blade spanwise flow of air therefore we avoid the more extreme vortex shedding.
Assuming then this anhedral is wanted and we can fix multiple lines across the central gap…
This network is then just as stable as any sheet.
Networks won’t tangle as much as the disconnected individual blades themselves could.
so a configuration with an external band is desirable
of course the outer tips will want bridle tether support too