you will get some color distortion with any 2 different colors, what you want to try to do is match the colors as close as you can...

bright pinks, shrimp oil

bright reds, egg oil

i prefer oils on yarnies over the gels, the gels make them like a sticky mop, and will lose the dexterity of the yarn, and the overall shape of it...

obviously if you have yarnies with white spots, the oils will tinge them the color of the oil a bit, but it doesnt matter, nothing in nature is perfect, just dont use blue on red/white, or you will make things difficult possibly... then again, you might find something that really works... best thing to do, is try them out, and see what works better than the rest...

for different colors, while you are curing your eggs, depending on how you cure them, SAVE the juice from them, different cure colors, create different juice colors, and just dunk your balls in there for a bit to absorb sent, or take a few of them and just leave them in the oil throughout the day...