Aww thanks!
The article I linked upthread from the Guardian suggested cooking the tomatoes in the caramel so the juices exude and can be reduced before baking
But I think that’s why they didn’t hold shape. I think one could salt the tomatoes to extract some liquid instead.
(Though with Apple tarte tatin and apple pie, I have poured off and cooked down fhe liquid after baking if there’s too much.)