In stores we receive hangers in boxes for the factory. They come in 20x20 boxes and about 3 feet tall. They have a cardboard divider at an angle.. in the center.. Poster board would work.. So you look into the box it looks like 2 triangles.. You then lay the hangers so the the hook portion of the hangers are facing the corners of the box..
I suggest you separate wire hangers from the plastic ones.. This way they are less likely to tangle. And of course shirt hangers from Pant hangers will need to be sorted..
Of course if you had a system of hanging PVC pipe or metal pipe in rows from floor to ceiling it would be ideal.. Then you just use a shepherds hook to pull down or hang up groups of hangers in rows and rows.. ..