When I worked in the packaging department at a previous job I learned a lot of methods for keeping shipments from shifting around during transport. The number one and initial method that we always used was the supple used of shrink wrap. It skid would be stacked up to 42″ high and needed to be well balanced. Beyond that the only other thing that kept our shippers on a pallet was being wrapped very tightly with shrink wrap. Using an automated machine the skid would spin slowly started at the lowest point and would work its way up to the top of the skid, then it would work its way back down again, then back up, then back down. It would do this until every inch of the skid would be covered with a minimum of three layers. This would ensure that even with severe shifting the load would hold tight and nothing would tip over.