I'm in the 'two holes is good' camp when it comes to bullets. First rule though is to put the first hole in a place that will allow the bullet to do the most damage to key organs etc and still have the energy to leave an exit hole.
In regards to the 'skin stretch', I still have a vivid memory of watching a forked antlered bull elk running out of the timber towards me about 150 yards away. One of my cousins took a shot and I remember seeing the hide on the off side stretch out at least 18" - 24" from the main body. TWICE - once with each shot. We found one of the core-lokts under the hide. Never figured out if it was the first shot or the second, but, we're guessing it was the first.
