@brandon, I’m happy to help. If you have an image with alpha, you only need to mix in the alpha with the mask coming out of the step node. We can easily do this by taking the oneMinus of the decal alpha and then using a max node with the step to create the combined lerp gradient. You can see it here:
I also updated your PG with the extra nodes. I must say it’s been a very long time since I manually configured a node material in code. I tend to prefer using the node graph and either parsing from a snippet or loading and parsing the json from my github.io.
This should get you up and running, but feel free to ping me with other questions.