When you use the wish menu, it generates a new item as if it was a drop. That’s why some clothes fit and some don’t.
Some items, like wheels, have a variable size. They are all ‘armored wheel’ items, but have additional data that’s rolled when an ‘armored wheel’ item is spawned. This roll happens on the display of the wish menu and when you actually spawn it.
If you wish for four armored wheels at a time, they’ll all spawn with the same size (iirc).