I am ignorant about the structural differences between the long cage double and triple Campag RDs. Could someone point me to the correct information or lacking that, edumacate me pleeze? Are the differences irrelevant to the above discussion because the doubles simply don't work?

I've looked at posts here "help educate me on Campy Ergoshift..." and read the artscyclery blog post "Science behind the magic" but I am still not clear about the difference between Campag double and triple RDs.