You also need to take into consideration the dish size too, on larger dishes the LNBs can be spaced out further. On an 80cm I can get satellites 4 degrees apart using two Black Ultras when they are touching but really they are not aligned spot on. For high power stuff it's not really noticeable but I notice it on my setup in Finland.
Having said that, on my setup, I found I was getting better results from a slightly misaligned Black Ultra than a properly aligned narrow 23mm Multiconnect LNB.