As a native English speaker, "I'll have a large small fries" pretty clearly means a large quantity of small type fries to me. It's the kind of thing you'd say s

As a native English speaker, "I'll have a large small fries" pretty clearly means a large quantity of small type fries to me. It's the kind of thing you'd say sort of jokingly, but I don't think anyone would really struggle with understanding it.