Who's Dominant?

I'm looking for some really specific information about how to tell which of my two pups is the dominant one. They're Italian Greyhounds, brother and sister (littermates) and eight months old. (yes, they're fixed, oh my goodness!!)

They've had to be separated a lot in the last few months because the girl pup had surgery for luxating patellas and so they haven't had as much opportunity to interact/ play/ and establish a pecking order as they will in the near future when she's fully recovered.

I've been told to watch for things like who wins when they have tug of war games, who backs down first when they both want something, who eats first, etc..

So far, they seem to be dead even. I'm confused!

The boy pup is bigger, healthier and stronger than the girl. And yet she seems to be able to win battles about half the time. Do you think that means she's dominant and that when she's fully recovered she'll kick his butt? Or will he assert himself more?

When they play tug of war, she often gives a low growl at him that makes him let go. Is that a sign?

But, when they curl up to sleep, he always seems to be the one on top. Is that a sign?

I've read information that it is important to know which dog is dominant so that you can feed him/her first, and do things to reinforce the pecking order, otherwise they'll fight more?

Any thoughts?

(here they are, duking it out!)
http://www.imagestation.com/picture/sraid168/pdf966a9f2621dba9b84c2fabc867a498/f41ff7a5.jpg

All I can say is watch them very carefully. The true Alpha will not want to hurt the "want to be" but the want to be will have no such compunction when the time comes. Watch very closely for one dog going for the other dog's neck - at just the point where the dog under attack can't retaliate. If canine tooth punctures neck, please take to vet asap. I would not leave dogs alone until situation is fully resolved. Which if problem develops it may never be. I lived with this for 5 years.

Theoretically, if you're doing a good job as the alpha dog, they won't be as obviously trying to dominate each other.

Dominance is also who can run faster and how the slower one reacts, who manages to be on top when they play, and if you're playing with a toy, who ends up with it in the end. Dominance can be shown by one dog putting its head on top of the other dog's shoulders or even putting the front paws on its back. Also, whoever sleeps higher (like on a bed, sofa etc) and doesn't let the other up. Whoever goes through a doorway first is a good teller too.