Watched it and one thing I don't agree with is that his first wash getting any excess oils and blood off the skins you have to rinse that stuff off or it's still in the feathers. I'd rinse then from what I was taught 2 drops of dishwashing liquid (it does help) using koolaid and other drink mix's, food coloring, easter egg dye tabs, with clean water then agitate a bit and use the white vinegar to set the color.

According to the video he says "it's still steaming", he adds the vinegar then puts the skins in. Some will say the water is still to hot but if you watch Davy McPhail dye saddles he has them right in the pan on the stove burner.

Even with the Veniards and Fly Dye from Anglers Workshop say to use white vinegar to set the color.

With Olive you'll want to check the color charts or if ordering take a picture of what color you're actually looking for to match up more of the same color because there are different shades of Olive dye.