*the envelope should be inflated to some minimum pressure (which I never quantified) which can be achieved with a BOSCH 12-VDC heater fan from a VW Westfalia Campmobile and should have a sewn-in,internal truss structure for triangulation,both vertically and horizontally.
*Without inflation pressure and trusses,the envelope will rise into high-velocity/low-pressure air,then reach an angle-of-attack which triggers burble,then stall,'falling' away from the airstream until it's slope is gentle enough for reattachment,then the whole process repeats itself,setting up a cyclical whip-sawing of the structure which cannot be dampened.
I encountered this on my T-100.
You can use a rigid spar to reinforce the structure,but then you've got to deal with that.
You can probably find online patent drawings of GoodYear Tire's Aerospace Division's U.S.ARMY inflatable airplane of the 1950s,which will show you their internal truss structure.
Without something like this to reinforce the structure,you'll have a rattlesnake's tail to deal with.
