I've been doing intros this way for about 5 years now, maybe 6. I've only had one animal involved, where the chins just absolutely refused to get along. I think the female involved is just a freaking beast, because I've yet to be able to pair her with anyone, and yet any of the males I've tried with her have gone easily into other pairs or trios. Very strange. The rest of the time it has worked out well for me.
Another thing some people suggest is putting the chins together in a cat carrier and going for a drive. Again, I don't have time to do this with 100s of chins, so I use my method, but others find that this works well for them. Most chins settle right down when you drive them somewhere, I'm assuming mostly because they are so nervous, so that by the time you get them home they have forgotten to worry about the new body in with them. I have not done this myself, although I have put two or three animals together after returning from a show with no introduction at all. That 16 hour drive makes them mighty mellow.
