No way in hell would I sit in this thing to London in Y. The next obese man or woman who sits next to me is getting a deflating puncture to the abdomen. The width of humans in modern era (Americans followed by Australians), is truly a thing of nightmares on reduced seat width.
Another great example of technology been able to deliver something which isn't neccesarily a good idea...
ULH flight are technologically possible, but the human body hasn't been upgraded like the engines and aerodynamics. This flight will be a nightmare for both crew and passengers....unless you are in Biz class or above...
And lets face it, that's where all the airline executives who think this is a great idea will be.