Whew! With the family away, I was able to get a lot of the work on the Horrors done. In the space of a few days, I primed, basecoated, washed and drybrushed 30 models. Then I drybrushed them some more.
Resulting Pink Horror:

I'm surprised with how well they've come out. If there's one thing to complain about, it's that they have a slightly "chalky" look to the highlights. The last bit of drybrushing, with a light pink, really made the relief pop, but may also have contributed to the look of being made out of marble. However, the addition of details like teeth, eyes, claws, jewelry - and on some of them, horns, beaks and feathers - may remove that impression.
The chalkiness is even more evident in a Blue Horror, but maybe looking at it this close isn't quite fair (the scale isn't clear here, but Blue Horrors are small):

I made the washes from photographic retouching dyes, to which I added a goodly amount of PVA glue and some dishwashing detergent. They worked really well. The manufacturer is out of business, but you can pick up old kits on eBay:
http://cgi.ebay.com/Retouch-Methods-14- ... 0665140361This is a unique fellow who doesn't rank up very well because of his long arms, so I'll probably designate him as a Herald of Tzeentch, a hero-level Wizard.

And here's a group photo. This is just 20 of them - I have 10 more.

I think the mixture of models and colors and the many arms in the air give them a suitably wild look. Like they just don't care.