Couple thoughts for you Randy.
At the stage the baits are at in the 3 pics prior to this post try using some clear laced with violet hi lite used in soft plastic making. Here’s a link for you.
https://store.do-itmolds.com/HYPER-HI-LITES_p_314.html
These hi lites work great in airbrushes as the particle size doesn’t clog the tips. The hi lite in clear will add a surface flash of purple across the baits in the sun. In about 1/4 teaspoon of clear add a couple BB sized dabs of the hi lite then use reducer a drop at a time to get it fairly liquid. When applying you don’t want to try and color the bait and a couple damp coats is all that’s needed. Then finish with your back and stencil colors. When you’re finished the purple [violet] hi lite will be seen when the bait is turned to view at different angles and in varying light. The hi lite creates a very natural appearance on the bait.
On the back where you are thinking a dark green, try adding a drop of brown transparent to the green and add a little green hi lite powder to this and reduce it some. The green back will have the same type of glint as the violet did on the sides. When you get the green set, thin down some transparent black well and shoot a very thin coat right across and directly at the very top ridge of the back over the green. The black will be more of a smoke and will help deepen the green without making it look black. Since the black is transparent the underlying green will come thru. I’d actually put just a bb size ball of gold hi lite in the black or in a clear over the black.
Note that the link refers to the colors as pearls. They’re a pearl pigment but are different from the other pearls in that these pigments work at the surface of the plastic or paint, not thru it like true pearls pigments do. They’re a hi lite powder like what other internet sources sell wherever soft plastic bait making supplies are sold. Netcraft and pouryourownworms.com both carry identical products and refer to them as hi lite powder.
Hi lite powder is a white based product and pearls are a colored base product. Hi lites won’t change the color they are in or going over while pearl products will in both uses. Hi lite are use as an interference color, one that pulls your eye away from the primary colors of the surface. Super cool results using these hi lites. Gold hi lite over orange or chartreuse. Green over blues and black. Blue over hot pink or over blue. Violet over hot pink or black.
In the case of your small baits where getting a violet or lilac color on as an accent may be problematic, the hi lite can over the colors you have but still tickle your eye with some violet to purple flash and basically stay invisible otherwise.