I think that the Aquarius is the best, because it is pretty big, easy to bind with, and comes off the string easily, but as you said, YYE is out of stock…
I think the Hayabusa is the best choice. Although it is a little bit small, you will get used to it, I don’t think it makes a huge difference. It is made of hard plastic, so it won’t bounce away like the Aquarius will, but it is still durable.
The Big Yo is, well, big, but it is hard for beginners, I feel. I still can’t really use it. It snags WAY too much. When I try to throw it, it comes right back usually. It also has hard plastic though, so it won’t go flying away when it drops.
So I think the Hayabusa is your best choice, unless you want to wait for the Aquarius to restock.