I take a black marker and blacken mine out, allows for total focus on the target and nothing to distract and pull my eyes off of the target. If it starts to lighten up just apply more marker.
I never used the bead. A properly mounted shotgun with your eye on the target is the key. Head on the gun, eye on the target and NO bead is required. Just like baseball and/or golf. eye on the target. if the shotgun is mounted properly your eye is the rear sight.
I haven't used one for years. During a lesson, a coach made me remove it. I never saw a need to put it back on. The only thing I use it for is to check that my mount is straight down the barrel, but you really don't need a bead for that. I have a small mid bead as well and it works fine for alignment purposes. I'd caution anyone beyond a new shooter that you should always be looking at the bird, not the barrel. That's one of the quickest ways to stop the gun mid swing.
I have one, but I never look at it. It is one of those coloured high viz ones. Came on mt Browning 625, but I never look at it, si I don't even know what colour it is.