Thank you, Greg. I’m sorry that I won’t be able to answer your question in the way you would no doubt like. For a start, I was born into a family which was both Christian and evolutionist, so I never in a position to reject spontaneous creation, YEC or any other variant of a semi-literal interpretation of Genesis, as I had never been convinced of it in the first place. My secondary school was staffed predominantly by Benedictine monks whose training in Christian views from Jesus, through all the early Church fathers up to the latest theologies never assumed that Genesis was to be taken literally. I think it comes as quite a surprise to modern ‘creationists’ to discover that their view - that every word of Genesis is to be understood as more or less a scientific statement - actually post-dates the theory of evolution. Scientifically speaking, Darwin’s publication of the Origin of Species did not overthrow any entrenched views about the literalness of the bible, it actually clarified the confusion which had developed over the previous half-century or so, which is why it was immediately widely accepted as entirely sensible by Church and secular alike. Subsequent controversy has been theological, not scientific.
Your second request demands ‘proofs’, and again, I will have to disappoint you. ‘Proof’ is not a scientific concept. It is a mathematical concept, and to a certain extent a judicial concept, but Science does not prove things. It is a model which demonstrates things to the general satisfaction of the community, whereupon they become generally accepted until somebody demonstrates that another explanation fits the data better, whereupon the model is modified or replaced. Your desire for a ‘smoking gun’ is very understandable, but wholly unscientific.
This and many other websites which cover the borders of empirical and philosophical ideas often discuss the meaning of separately created ‘kinds’, but to my mind rarely achieve consensus among themselves. As George shows, most creationists reject an identification of ‘kinds’ with ‘species’ and allow quite a wide diversification of original ‘kinds’ into hundreds of modern species in an evolutionary way. The crunch-point, that single ancestor of a number of modern species which must have been spontaneously created, is never well enough defined to be convincing to me. If a ‘dog’ can diversify into ‘wolf’ and ‘poodle’, then I cannot distinguish why a ‘carnivoran’ cannot diversify into ‘dog’ and ‘cat’ or some earlier mammal into ‘carnivoran’ and ‘ungulate’ and so on. Various semiscientific attempts to show that this or that evolutionary process could not have occurred are unconvincing to me.
To conclude then, your asking me for the ‘smoking gun’ which convinced me that evolution was a better way of understanding creation than ‘Creationism’ means nothing to me. I suspect that if I asked you for the ‘smoking gun’ which persuaded you to reject evolution you would find it equally incomprehensible, in that you never accepted it in the first place. Blessings.