I think I recall someone using a thin smoke and loading it w/ large white square flake. It was different and nice. A thin pearl w/ large black flake would work too. I don't know that I'd use chartreuse, crappies around here are usually solid black and white with maybe a little gold sheen, but if they show some yellow by you when they're young, go for it. It would depend on the mold you were pouring I think. If I were doing the 3.5" swim shad I would start with a pearl belly, poured smaller than I normally would. I'd use the above mentioned smoke white flake or pearl w/ black flake w/ maybe some holo silver for the middle and a smaller than normal smoke w/ maybe some black flake for the top. All of those colors would probably see a lite dose of gold or bronze hilites. Maybe some green hilite in the top color, depending on the water I was going to fish.
I'm going to try and shoot a video of 3 color swimshad pours this week after work some time. Maybe I'll try this out as well.