Hey folks, I'm going to mill my duty M&P 2.0 for the Leupold Delta Point Pro (I'm keeping my Glocks unmilled for now). Having the slide cut to accept tall rear irons will probably be the most reliable option but I like how the Delta Point Pro iron sight is modular and adjustable. How durable are these iron sights? Do they work as well as regular irons? I'm afraid hard use will knock it loose or cause it to fall off. I can't tell from the pictures but the iron sights seem to have a narrow U notch. Is that the case? Thanks.