hey there, i have a rem. 870 for HD (the all black with factory mag tube ext.), all i have on it now is a hogue tamer pistol grip. i am going to add a mesa tactical shot shell carrier; however, i was curious to know if anyone uses the xs sight systems big dot tritium front site (can be seen at brownells here). if you have them, how do you like it? how does it glow, how long does it last? does the sight itself stay mounted (as it is applied with epoxy over the existing bead on the remington 870). thanks!