In reply to CussedTomato:
Yeah, unfortunately, as others have said, until you have properly used a pair of technical footwear for the purpose you got them for you can't really know. Now you do. I have the opposite, I wear my Boulder X slightly small, intentionally. Ended up with that size through experimentation. Wearing them while sat down, around the shop, in the house etc., when my arches are fully up is REALLY uncomfortable, yet I can walk and climb in them perfectly comfortably, more or less indefinitely.