As regards conspicuity colour schemes - there was a study some years
ago by (IIRC) the RAF that concluded that black was the colour that
allowed earliest visual acquisition because it had the highest colour
density.

This is purely personal opinion but I think that there is a lot of
confusion between "attention keeping" and "ease of visual acquisition"
and I think that brightly coloured gliders are a positively bad
thing. They tend to attract and keep other pilots attention - partly
involuntarily and partly cognitively as you start to ponder what a
nice bright glider it is and how well it stands out against the
scenery, all the time reducing look out elsewhere. I discipline
myself to look elsewhere when I see a coloured glider. I have never
once thought that I have seen a coloured glider earlier than another
white one flying next to it - even flying against a snowy
backdrop.

We have several RAF cadet scheme gliders at our site over the summers
and they have large dayglow areas on the wings and reflective strips.
I have been studying from the ground whether I can see them in the air
any sooner than the similar white club gliders and I am completely
unconvinced.

Good lookout supplemented by Flarm are the best we have at present.

John Galloway