Unfortunately, even though I am only 5'10", I am not as limber as our friend, Mr. Coyote. I have the Motorcycle Larry variety of lowering pegs which I believe were designed specifically for the the NT, but are no longer available. IIRC, they were advertised as lowering by 1". On the plus side, 1" makes a huge difference and I found immediate relief from the previous cramped riding position. On the down side, it does in fact reduce ground clearance and I have scraped pegs on a few occasions, and I am by no means a "spirited" rider. The first time it happened, was a little unsettling, but because the stock internal spring system is maintained, it didn't dig in and send me into a high-side. When it's happened since then, it's more of a "oh, there you are" moment. Be advised that adjustment to shifter and brake pedal will be required and it took me a while to get that just right. For some reason the brake light wouldn't come on, so I had to futz with it for a bit.
Be advised that aftermarket lowering pegs does change things in some unexpected ways. The design on mine actually pushes the peg out further away from the frame, so in order to shift or brake I have to make a "toe in" type of maneuver that wasn't necessary in the stock location. Also, the pegs you are looking at appear to be longer that stock and will result in the same condition I just described. That might mean even less clearance in corners, although I can't be certain.
Good luck!