I was going to put one of the pinky extensions on the 7rd mags and was looking at all the options. For the price of some of these +2 kits you can get another mag, at least that's what I think I'd do.
I have one on my Shield 1.0. A great addition! A bargain compared to other mag extensions. Easy, no tools installation, works flawlessly. May be buying a couple more to increase 8 round mags to 10. Best buy!
You will not be disappointed. I'm a little klutzy but following the installation video on YouTube, it was easy. Other extensions run $30 and are not as nice.