Overall I think the particle spray effects are pretty neat. However I do have request. Some particles can be large and opaque enough that you can lose site of the area you are trying to spray on. For example, the Burn particles can cover your view of the mesh while spraying, covering your view of what is going on. I'd like an option to turn off the preview of particles before they hit the mesh.
To augment this, it might be nice to have an option to highlight or show a hit target circle on the mesh to let the artist know the radius/boundary/mask of the paint about to hit the object.