It was a quiet day and no customers have arrived yet, so Jon decided to head back to check on the secret behind everything. First he entered the back room where various magic items were stored.
Jon walked up to the back wall of that room and just passed through like a ghost into a small chamber. he put his hand on a panel in the chamber door and a light scanned his hand print, then scanned his whole body, then scanned his eye. A voice chimed up saying "activate voice recognition" Jon said "open sesame" and a green light lit up and a secret door slid open.
The new room had a round glass table in it lined with dozens upon dozens of wishing stones set on a brass ring built into the table top. This was the secret behind making so many items, may of which can exceed the stones limits.
You see jon merged more than just knowledge with his alternate universe selves. He found his selves whose knowledge of things like magic, technology, biology, and even things like art and religion were the best among all possible jon's and he merged bodies as well as minds with them. after he merged with them and gained their knowledge he took their stone and added to his own.
Jon touched the brass ring on the table top, a ring made to be able to conduct wishing through it to other stones in contact with it.
Jon said "I wish I had a ring that changed the wearer into the body they most find attractive"
Something strange happened as he spoke, all the stones lit up, his voice echoed in a strange unnatural way as each stone took in a bit of the sound and put a bit of magic into it, and a ring appeared on the table.
Simple stuff like this was easy, even with the old stone, but with all these stones he can create items that can exceed the power of any one single stone.