That's a great bucket, Sadie, and I agree that handles would make transporting it, if you needed to, much easier. The only drawback I can see to using it as a growout tank is you wouldn't be able to see your babies, except from the top. The advantage to clear containers is you get a great side view, and consequently can see right away when the babies begin to display aggression.
opposite armor, it sounds like the clear crates you've found would suit your purpose just as well as a tank, for a fraction of the price. Do you have a link to a pic of them, or a product like them? I might be interested in finding something similar.