Thanks for the reply. I've used XS BDs for a while (the set on my carry gun are stamped "AO" instead of "XS") and had just about convinced myself that the rear trit was unnecessary, but have been wondering if the Trijicon HDs might not be 'more of a good thing'. My duty gun has Glock factory NS which I use a black Sharpie on the rear lamps-they still glow faintly in the dark, but they don't overpower the front in any conditions. Unfortunately, the finish on both front and rear succumb to holster wear pretty rapidly.