Draping a solid over a solid with Shell Force causes error?

I've been using Grasshopper for a while, but I'm only recently getting into Kangaroo. I was trying to create something that would help simulate the draping pattern of a mesh tube ring over a neck form, and it seemed to work pretty well with just Collide Mesh, Gravity, and Springs from Mesh... Except that the tube flattened itself out. OK, fine, so I add the Shell force component to help maintain the volume. This also seems to help, until the mesh tube goes all nuts and the points bounce everywhere and it destroys itself instead of laying nicely on the neck form. Depending on how I adjust the parameters, it either starts distorting right away or once it hits the neck. When I try to drop a different shape instead of the tube, like a ball, it works absolutely fine, so I'm not sure why this one mesh shape has such issues. I even tried building a tube in Rhino and using that instead, tried a more basic mesh ring, tried rebuilding or subdividing my ring, tried a torc shape, etc, but they all go bouncy. 

Can someone please tell me what I'm missing, or if this is a bug, or if there's a workaround for it? I've tried everything that I could think of, so any help would be much appreciated.