Hi,
DecalMaster v1.3 is now on store. With the new version the output texture quality is even improved.
Can you see the seems on the following image? (you can click to open a larger image)

The texture is the sample Victoria 4.1 texture (1024x1024) - the smallest texture for victoria I have, to show the results on the worst condition. Two decals are applied: one in the torso back and one in the shoulder, to cover the "torso-limbs" seem.
The image is rendered with DAZ|Studio with no postwork on the texture applied or in the final image.