I have used Spotone for a long time, I handle it just like water colors. I put a few drops of each color (1,2,3.) on a white pallette glass/plastic/ceramic,
and let it dry. Using a 0000 or smaller Kolenski Sable brush slightly moisened
with water and photoflo ( a drop of dish washing detergent works just fine)
mix the color necessary to match the spot and apply it. Color dye applied to the same kind of pallet works very well also. Done properly you cannot see the applied dye on the print surface. BTW I hate spotting even though it is very easy and quick to do. Sounds like we all are using basically the same