I have not used the UV Blast, but here are my experiences with two toning regular PP. Heat the heads just enough so the base coat is still a bit rough when you remove it from the paint. Swish if through the second coat and it will adhere to the first coat by friction and residual heat. Hold the jig a couple of inches over the heat source for about half a second per side so the paint doesn't fall off when you handle the jig before baking. Don't sick it close to the heat source and you won't have a problem with the color changing.
Has there been any studies on whether crappies can see UV light? I know some salmonids can, but different fish have different vision capabilities. Haven't heard one way or the other for crappie.
Don't worry, catch crappie.