I've been trying to get this to work, but haven't managed to. What I'm trying to do is set a bunch of values, convert that into a JSON string, set the result to a text box object, copy it, and then in the event editor, use it as an expression in the 'load table from JSON string' action. From one of your examples, it gets this:
{"HP":{"L1":"100","L2":"105","L3":"110"},"ATK":{"L1":"7","L2":"10","L3":"14"},"DEF":{"L1":"1","L2":"2","L3":"3"}}
If I paste that into the expression, it doesn't work at all. How can I get this to work?