To be honest, I think what you're wearing (up to and including the use of lights) makes very little difference in almost all cases in practice. For instance, drivers can easily see pedestrians who have none of this stuff on, as you can test by going to your local zebra crossing of an evening and conspicuously look the other way to the approaching vehicles as you make to cross.
I never got around to posting about it but a week or two back in the car, I came very close to taking out a cyclist when I pulled out in front of him at a t-junction. Luckily he was going uphill, so he wouldn't have had to brake or anything - but it was just that, luck. I didn't see him until I was more than halfway across the lane. Downhill at a good clip I think he'd have had to brake pretty hard.
He had lights and hi-viz/reflectives all over him, and I am obviously obscenely attentive to other cyclists - just didn't see him. This is one reason I ride out from the gutter especially downhill, so as to be where people's brains are expecting a hazard to be.