It is totally frustrating that people think they have Araucanas. Even my dog vet says he has them, and that he was surprised when they layed pink and speckled eggs instead of green. (He said they were rumpless, though, so go figure)
But over to Quirky's question- Lanae (Cashdl) has the best instructions for incubating Araucana eggs. I was successful when I followed them the first time I ever incubated.
This has been my experience so far, and I am on my third hatch in a home-made incubator:
Shipped eggs will have lower hatch rates than local eggs. My first attempt incubating my own eggs with Lanae's instructions gave me 100% success! (these were Araucana/Ameraucana eggs)
Also, if your temps are a little on the low side, add a day or two to your expected hatch date. In fact, give yourself an extra day (22 instead of 21) on the due date regardless, so that you are less inclined to think you killed them all if/when they don't hatch on day 21. My chicks hatched out on day 24, because I was so worried that I was going to overheat them (my heater was not consistent and would spike to 105 without warning) that I kept the temp betwee 95 & 98.
Also, keep in mind how a broody hatches her eggs. She will get off the nest for a short time to grab a bite to eat or stretch her legs. She doesn't stare at a hygrometer, worrying about humidity. The temperature under her does fluctuate without hurting her babies.
I guess what I am saying is that totally constant temp & humidity is not crucial to a healthy hatch. If the temp drops to 95-96 for an hour, or if it spikes to 103-104 for an hour, you didn't blow it.
Oh, and the dry hatch method is pretty awesome, because in New England, the ambient humidity is the same as the dry hatch, so it's really hard to mess that up.
I may have gotten lucky, I'm not sure. Maybe more experienced hatchers can add to this.