KoolAid!
So I've only dyed skeins of wool with Koolaid, and I'm imagining the cover would be denser, and require more powder.
I got some neat colours by mixing two different flavour packages. I liked dyeing with KA because it was relatively simple, and foodsafe (meaning I didn't have to worry about poisonous mordants, separate containers for dyeing vs food). It was sort of revolting to imagine my childhood birthday-party intestines painted such dayglo colours though.
Another issues was the smell....the wool smelled very artificial and candy-like. I found it did fade substantially after the first few days...
Anyways, heres a good tutorial at knitty, and I'm sure there's tons on youtube.
http://www.knitty.com/ISSUEfall02/FEATdyedwool.html