Assume you are south,after double,would you bid 4♠ or pass?
What's this double? I think it is takeout or cooperative penalty double.
If you think it is takeout, it is reasonable for you to bid 4♠.
If you think it is cooperative penalty double, it is reasonable for you to pass.
So I have been wondering how to estimate for it.
Now I would give everyone JEC hand for reference.
Result : 4♥WX-3 500
Another table :
Result :4♠S-3 300