Re: Visibility of course marks
We can't have permanent marks, so we have to set marks on race day. We use large yellow or red inflatable marks, and even those can be tough to spot in the distance. White is a terrible colour to spot. Pait the marks orange or yellow, and, as Faster suggests, add a flag.
Of course if it is a permanent mark, then it's position should be known to everyone, and there really isn't any excuse to not have a waypoint for each mark, even if it is just on a smartphone!
1979 Santana 30 Tall Rig