Gets to a point, Greg, where you won't see a sharp rear sight, no matter where it is and the front will have a 'glow' as well. That's where mine are now.
Sight design then becomes more important than position and the easiest to see for some aging eyes are wide V's (Express sights) with beads. The fuzz in the wide V doesn't hurt as much as with narrow V sights as the ears are so wide, the steel is still quite distinguishable and the bead, although fuzzy, still gives an accurate sight picture. We know the ball strikes in the centre of the bead, so the fuzz or halo doesn't disturb the actual impact location. Wiht a fuzzy blade, the top is not distinguishable and that makes for trouble.
With bead sights, the bead (small or large diameter) is raised above the bottom of the groove to give elevation for longer shooting - which practise will make an automatic adjustment in time. Usually about a 1/16" is good for going from 50 to 100yards. I usually sight my trail rifles for zero at 25 yards. This puts them 1/2" or so high at 50 yards and raising the bead (or blade) 1/16" gives a 100yard zero.
With a wide, shallow V sight, the bead sits in the bottom of the V. I like to cut a very small, shallow, easily visible notch there as a more vivid indicator of the centre. I sit the bead on top of that notch. It is barely visible but I feel it helps with accuracy shooting. When game shooting, this sort of sight is the fastest open sight there is. If the design wasn't the best, the dangerous game rifles & "best quality" modern and antique ctg. rifles wouldn't have them.
in my honest opinion
Several of the guys here have tried them and like them.