What's been working is a heaver gauge shoelace string for lashing it to the truck & a wider drogue.  The heavier gauge string doesn't come undone.  Still a nonzero chance a PLA piece could bolt on & extend above the container.

It clips on symmetrically.  The drogue drifts left & right with the camber of the road & wind.  Too wide & it goes off the side.  Too narrow & it flips over more.

It tends to hug the side.  The full 4k camera, drogue, motion control mount burn 500mAh/mile.