I am about to return to the world of show Yorkies
after a very long break, and I too have been researching the pros and cons of oiling-I had a Multi BIS winner back in the early 80's and his coat was oiled-it was a given in those days that show coats were oiled. From what I can gather it is very much a matter of what suits your particular dog, and when I eventually get my pup I am going to experiment. I can't remember having any problems with oil on my old dog, or with his coat after he was retired and clipped short, I only ever oiled his hair, it never got on his skin, I can't see that it would have any effect on the natural oils a dog produces themselves.