It looks like the ruby red is a shade or 2 darker than the candy. Both are gorgeous colors, I have a candy red 13 and love the color difference's depending on the lighting.
Your right about the lighting, early morning sun, midday, and then afternoon car looks totally different. I wasn't thrilled about a $400. premium for the RR, but it is a great color. Since it is a 3-step painting process, I wonder how much of a pain it will be to replicate one day down the road when it needs a repaint.
yep they are quite a bit different. i put my red candy next to a rr gt and was amazed how much different they were in the sunlight. both colors are very nice!