If you have to choose between the two, go for the N50-3 again. The N9 is basically a little slower N50-3.
I think you've psyched yourself out of this racket. Visualise the math of the entire racket structure and how the grommets would add to the air resistance. It's immeasurably small. You're making up BS excuses coz you want a new racket.
I think it makes those edges about as bulky as an armortech frame, so it's fairly significant. Either way I have an n9 now, the 50 will still be in my bag. In some ways it's a little lucky, they've just increased the price of the 50 et to 110.