A thing to think about that may not have a thing to do with this question. Red end of the spectrum will save your night vision.
While I get where you're going with this, these are fiber optic sights, not powered optics. Without light that front sight isn't going to glow, regardless of color, and your night vision won't be affected. If it is glowing then you have light and don't need to worry about night vision (though honestly it's not like either color is really casting light at you, it's just capturing it).
Have you had any trouble with the rod loosening or breakage...and what brand are you using.
I'm using Dawson Precision Charger type sights with a black rear and a green front. If I had a gripe it would be that the coating on the metal body of the sights appears to be either a black oxide or bluing. I don't find they just scratch normally, but you really should tape up the sights when you install or you will get some finish loss. Now one positive of the finish is that you can use say just a Birchwood Casey bluing pen and it fixes right up.
I've only got 700 rds through them right now but I really like them. I've had Truglo TFOs before this but the metal housing for the TFOs really covers a lot of the fiber rod and they honestly don't glow that brightly (IMO). The Dawsons glow like a Christmas tree, especially when you start getting near dusk (which is when my astigmatism really gets problematic). While the housing for the Dawson front sight is smaller than the TFO, I actually find it more rigid than the TFO where the TFO housing was sort of thin. The Dawson seems more solid.
I also like that the front sight is a bit thinner. At first I was worried it would be too thin but I haven't found that to be the case, even in a defensive handgun course where we were only allowed to use one hand. In that course I was making fairly easy hits to a small steel torso at 25 yds one handed. Some of the defensive front sights these days are about as thick as a tree trunk in order to be visible, but the fiber optics give you that visibility while still allowing precise shots.
Now I have seen my front sight "loosen" up a bit, but really this was on me. When I replaced the red rod with the green I didn't have a torch lighter so I used the gas burner on my stove. Now the rods melt quickly when exposed to a direct flame. When I went to melt the far end and seal the rod in place I cut it a bit long. When it sealed in place it seemed tight, but after 700 rds I see now that I left it maybe a 1/16" longer than I needed (I was also worried about getting too close to the stove with the sight and probably didn't get as close as I could have). It still works just fine but if I really poke at it I can wiggle it back and forth a bit. Honestly though even in dry firing it, much less shooting, I can't tell. I think a torch lighter would have let me be a bit more precise at this and the lighters are cheap, I was just impatient.
The rod itself has held up just fine. The Dawsons expose it well enough to catch the light, but without that little cut they leave in the housing for a razor it wouldn't be easy to cut or snap. I've done dozens of presentations at this point with no issue and I really think you'd need a direct impact to the rod to break it, which isn't overly easy given the housing. I don't worry about it breaking while shooting. My plan at this point is to keep shooting it on my training Glock 19 but in a few hundred more rounds I will probably buy the same sights for my carry.
