well the plugin is open source so you can probably just adapt the code from the plugin into a script
I recommend that when you press the Custom Decals button, it should let you upload files, like how EthanTheGrand does that for his CanvasDraw plugin, and add some customization settings so we can change it from 5, 5, 5, to 1, 1, 1, the current dock ui is boring and only have a button, add another button for that and do some docking with the customization 
anyways great plugin! I really appreciate it
(sorry for delay)
is it actually possible to convert parts during in-game using an decal