I have Williams fire sights on both my 94's. The one made in 1949 has a .290" wide ramp and the 1979 has a .340" wide ramp. For years I had a .340" wide lyman ivory bead sight on the .290" pre 64's ramp. Never got snagged on anything or otherwise caused any problems. A little bit of overhang ain't gonna hurt a thing. Now I have a .250" wide sight on it and that works fine too. It really doesn't look bad either way. Tell your buddy to do himself a favor and go with the green fiber optic. I've used both and the green shows up much better than the red in really low light.
