arranging x 5 teaches more skinning than arrange all.
When it comes to the moment of skinning itself, arrange all skins and arrange x 5 skins teach the same, which is notably better than a skin without arranging.
IMO, it boils down to how often you have a new dead mob to skin. I'm fine doing arrange all + skin because any exp lost from not arranging x 5 is made up for in the time where I'm killing a new mob instead of arranging over and over.
Uzmam! The Chairman will NOT be pleased to know you're trying to build outside of approved zones. I'd hate for you to be charged the taxes needed to have this place re-zoned. Head for the manor if you're feeling creative.