If those guys really took 2-3 days to paint a single head, then we are getting deals of the century paying a measly $100-150 or so to get them done.
It could take that long, but like I was saying before, they may be doing batches of heads where they do the base coat for all of them, then let them dry, then the base skin tone down, let it dry, then start applying washes, etc., or whatever their process is. I would like to see JOhnny chime in with his usual painting speed, since he's one that that frequents these threads with a lot of experience doing high quality head paint work.