They look great. The airbrush will allow you to do things that plastic simply will not.
Now get some createx clear gloss top coat and mix in a contrasting color of hi lite to you back colors and give them a light coat before sealing. Thin the top coat down really thin in your cup before adding the hi lite powder then add just enough powder to be able to "just" see it in the paint. One thin, but wet, coat. Let dry and seal. If you use green or blue hi lite over the aqua back of these baits the hi lite will blink at you as the bait rolls in the sun and creates a super nice interference color that'll be there at times and gone again without bouncing your plastic color around.
You should get yourself some color shifting pearl color for the real dark color backs you might make.