AFAIK, that's not 6 full U47, but rather 6 M7 mounted in 6 head baskets. The test was conducted with the same one U47 body...
Anyways, 6 U47 headbaskets fited with those M7 is enough to get me drooling...
Too bas he only had 6 baskets, so he decided not to include a Neumann KK47 in the test...
Axel