Think of it this way. 99% of the stuff you see from people, golf pros, so called experts is crap. Also, this is the best explanation I ever got from someone I really respect (my instructor):
At setup address position, your hands should be the same distance away from your body regardless of the club. Since that is the case, the longer the iron or wedge length, the flatter it should be to accommodate the impact position. For me this has always held true. My 3 iron is 2 degrees flat but my LW is "standard".
Just a thought for you to consider.
Cheers
-Burk
Sent from my Sprint LG G5 mobile device