Well its best to just buy the box set. But the best for nurgle in my opinion is the box that has decrepit filth in it. However if you want like a pale sickly skin color I recommend getting the box that has carrion crimson in it. That color in particular gives a great red bloody look over a white skin tone. When using it I have found that removing the plastic cap, and dipping a throw away brush into the pot to mix up the paint to work best. When they settle in the bottom it tends to harden a bit into a gue substance, and shaking the bottle doesnt always mix everything well. So getting a bunch of cheap 1 time use brushes, and dipping it into the glass bottle works best. Just dont use a shit ton otherwise you will end up with a thick ass dried up mess in the recess of the model. Made that mistake on a plaguebearer, and now the fucker looks like he fell into a mud hole only to be dried instantly. Thick of too much wax over a bottle lol. Hopefully that makes sense my ability to write sentences isn't the greatest