I haven't used ps61, but I have used ps21(fluorescent red). It's the one for the porsche rsr body. The color is bright with a white backing. But what I did to test it, cut off a scrap piece of lexan body, about the size of s business card. And test spray it, all ps61, mask off half and spray with a backing of each color. That way you can see how it looks in the light. I started doing this with all my cans of paint. That way I have a reference color already in a "swatch", sort of like going to the paint store and they have hundreds of color samples in a ring to match the right one.
I will post pics when I can dig my samples out and show you what I mean.