I love tweed and find myself intrigued by thoughts of a Tweed Dinner jacket. I'm pretty sure I would wear it on a selective basis...sort of a GTH dinner jacket! We regularly host family dinners...sounds like some great opportunities to me!
I don't think this is ever going to be really "correct" anywhere, certainly not for evening. It is much too casual -- the color is too light, it is 2-button, has flap pockets, and the cloth is too coarse.
I do like it, though.
You might get away with wearing it to a country ball where you were also the host. No one could say very much about that...
I'd classify that as a house jacket as opposed to a dinner jacket, very comfortable and warm. It just doesn't seem to have enough formality for a dinner jacket, even as the host (though you can, of course, wear what you like).