Hey I get art poaching, and also that graphic design work is just that; work and as such has intrinsic value not only to you but the audience. That being said this is a coloring of an another artist's work and it's not like you gave the illustrators any credit since it's transformative in nature would you consider maybe scaling down your signature of not deleting it all together? I want to use it as a wallpaper but the huge watermark signature is hosting and really in my humble opinion you will want your original creations protected far more than passion practice pieces. Just my two cents, let me know if you take my advice cuz I'd love this as a phone background, keep up the good work.