marbling can be done with a 2 color injector alternating pressure on each injector while turning the blending block. I have done a good bit of it. It tkes a feel to get it down. just a little pressure on each one.
scales I have done on 5 inch swim baits and it aint much fun. On small baits you need very small mesh to make it look right and its pretty time consuming to do it and make it look good, it needs to be dipped after to seal it.