I think he is wanting to know how much "pull" the walls can take if the clothes are hanging from bars or rope attached to the side walls.
Best bet is "wardrobe" boxes from a moving company. Used these many times while moving in the military. Each box is approximately 4 to 5 feet high and has a metal pole that locks into the sides. Clothes can hang but will not fall off the bar as the hangars are held in place by the top flaps. Also, much easier to move the boxes than individual bunches of clothing.
If they remain in good shape after shipping you may even be able to get a partial refund.