Thanks for taking the time to do the videos. Only the YouTube one seemed to work. As I said before, video's just don't do lamps justice. This is particularly true when it comes to ones that aren't very bright. On video your two seat stay lamps look almost like candles when actually they might be fairly bright. On the other hand a video will make a moderate lamp look almost super bright. Then when viewing the really bright lamps they look so bright that they appear like a super ball of light. Eventually once the output gets so high most videos can't accurately depict the variance in intensity.

Just a couple days ago I purchased a couple small/cheap usb rechargeable lamps to try out on my seat stays. Just one alone is not very bright but would be useful enough to get someone seen if on flash. Two, are a bit better but when on steady they are just barely adequate. Now coupled with my good Performance/Serfas clone lamp on the seat post the overall effect is much better, particularly when someone gets closer to the bike.

I know that having a lamp on steady can be useful so likely I'll use the smaller lamps on steady. I like the brighter lamps on flash for two reasons; first, they attract more attention at distance and secondly, well....the battery will last longer when on flash. IMO, it is more important to be spotted at distance. With a "triangle pattern" array and a 100+ lumen helmet rear lamp going ( not to mention wheel lights and standard reflective bike clothing/shoes ) I would be hard to miss at night.

Of course for added daytime awareness I would probably only use a single lamp at it's brightest setting. I have a special torch mounted under my seat just for this purpose. Rapid 3-pulse/pause flash pattern/ amber led and about ~100-150 lumen ( over-driven ).