I too have been considering the fiber optic front sight. I just havent desided what I want to do for a rear sight. Being I will need the proper highth to work with the rear sight. Im looking at green. Heard it was better in low light.
Give you a tip. If you go with the fire sight, measure your ramp width. The info on Midway and Brownels site say the medium width. .340. I talked to the folks at Williams, they told me that when Remington took over they started making the ramps for the Marlin 1895 narrower. .250 I believe.
I have the Williams on a couple of our 30-30s and they do work, as advertised, in our always dark north woods. The FO bead is a bit large for my taste as far as range work and be warned that the light pipe can snap and break with a good whack from brush if your poking your rifle though the really thick heavy stuff. For that reason, not sure I'd trust the Firesight on a rifle that was doing duty as a backcountry self-defense bear gun. For most hunting situations, though, should be fine.
IMO, the 1/16" wide red dots as sold most everywhere are great for speed, but too fat for precision work. I see some European imports that appear to be about half that size, metric for sure, that I really like. I just can't find them as an aftermarket item.
I used green on my hunting handguns and green is fast to pick up but red is more defined and works better for precision shooting. also I found the red is better hunting in the snow. in the snow with a lot of light the green seems to wash out a bit while the red becomes easier for your eye to pick up.