Hi,
Probably time for a little reality check... Unless you are just flogging the living Hexx out of that 919 everytime you get on it, or putting in many hard Track days, or seriously racing, it VERY unlikely you would see much difference in any aspect of wear or performance with any good, major brand oil that is correct for the bike. That said, some oils do seem to have a little better shifting quality. If you seriously expect to get 100,000 miles out of that motor, then, yeah, oil selection becomes a little more critical. Ditto if you are an ultra hardcore type that WILL actually, tear it down and mike internal components and are preoccupied with wear. The vast majority of bike owners never hang on to a bike long enough to ever tell what impact oil brand had on it. My guess is that you would have 80,000 totally trouble free miles on that bike using Honda dinosaur GN-4 if you change it at reasonable intervals. I have a friend with a VFR800 with 64,000 totally trouble free miles on it and the valve adjustment is still within specs....he uses the "cheap, average quality" Honda GN-4 petroleum oil and changes it reasonably regularly.
I do NOT work for Honda or have any affiliation with Honda, but I do have a very close friend who works in their engineering dept. He is emphatic that their oils are "good" and DO go through performance testing to meet a rigid standard and provide levels of performance to assure customer satisfaction. As he says: "It makes no sense whatsoever for a reputable manufacturer to put an inferior oil into thousands of high quality, well designed, high performance engines." (which Honda and most motorcycle engines are.) They also do not want to pay warranty claims due to lubrication failure. (Duh!!) Are their oils "overkill" or "way in excess of normal customer needs"?? No.... Can you find a "better" oil (As Bill Clinton says: "What do you mean by 'better'?")...possibly....will your 919 know the difference....very likely not (unless it is in abusive service or you put 85,000 miles on it.). Prices may or may not be a good deal; that is your call.
To most of us, bikes are a hobby and we address that in different ways. Some enjoy exploiting the economical side of maintenance and extend oil changes, etc. and others change oil and filters in their "baby" "way too often".... different strokes for different strokes.
All this said, Amzoil is good stuff, no question. I have used it a good deal and (not having torn down the engine to measure wear on the components) felt it was good oil. However, I have never had ANY problem over 40 years of riding with any "good" high quality brand of oil....but I change the oil "too often" so it is kind of hard to tell. Good luck!
Regards.....