Ok, so my apprehension about a 50% tourismn to others could be bigger than 100% to a specific civ is baseless. But how much is it in general? 5 times the toursimn output changed by the modifiers? Something like that? I would like to do some calculations based on that, cause like Minh Le said, all civs except one gaining 50% of the trade route tourismn is a lot of tourismn. I could do some maths for you, to get a better view for a balanced tourismn, and start the next patch with an already fitting value.