Drill the mounting hole on the floating rock to 3mm (ie use a 3mm bit in a cordless drill). Drill to around 3-4mm deep.
Break off the little nubbin on top of your clear upright pole for the flying stand (use the small one).
Try them for fit. It should sit a couple of mm lower on the stand, and the weight will be supported by that much extra plastic, as opposed to the 1 cubic millimetre of plastic it had.
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