Where in the blue hell are people seeing 35 yard gaps between the 7 and the 8 iron? I'm not believing that until I see TrackMan numbers. I have about 40 rounds on my 790s since last fall and have certainly never seen anything remotely close to this. I have my normal gapping of 12-13 yards between clubs. I just do not believe there could be 35 yards between sequential clubs.
Well I don't own a trackman but I'm pretty sure I know how to measure distance. I experienced it. The 7 with the slot vs the 8 without was considerably longer. I'm also a better than average iron player. It's real. Maybe not for you - so that's a good thing! But, just because you haven't experienced it doesn't make it less real.
Every time you hit balls or play a round you play a 30 yard gap between 7i and 8i with your stock swing and similar contact? I just have a hard time believing a sole slot and 4.5° gap between clubs cause this phenomenon.