Well, which grey likes you the best??? That's how I chose my grey, or shall I say my grey chose me. You think two is hard to choose from, try four!!!! I was going to take the baby home, had already names it. Sweetpea. Because that was the one the breeder considered the sweetest. I had never seen the babies until I went to pick up my new grey who was 3 hours away. Well "Sweetpea" nipped at me and wanted to go back inside her cage! The one who chose me was the oldest, my Ana Grey. So the breeder, my grandson and I decided the choice had been made and I have never regretted it. Ana Grey chose the right way, she chose me.
I agree with the others, let the breeder/pet shop wean the greys completely. I believe it is hogwash about if you feed the babies formula you will bond better with them. Nonsense, my grey is my friend and she trusts me totally. Frankly I hear a little reluctance in your post about handling the baby greys. Greys do nip/bite, they do scratch with their claws so if this is going to be a problem with you, perhaps you should think twice about becoming a grey owner. They bite, they scratch, they are messy eaters and they do poop a lot. So if I wasn't confident in being able to handle any of these habits then I would just walk away from becoming a parrot owner.
You have a beautiful cat on your shoulders in your Avatar. Cats and birds are not natural friends, please think about that before you bring a parrot home. I don't mean to be negative its that there are a lot of things to consider before become a bird owner. I see that you have been a member of the Grey Forums for a very long time, I commend you for joining to learn about greys. There is a lot of information in the threads here that can help you in so many ways to become a great parront.