I wouldn't worry too much, as long as you keep up WCs. At 1 inch, I wouldn't even throw them in any bigger of a tank than a 20. Helps get them settled with the surroundings and it's much easier to pellet train (you should look into that while they're in a small growout).
BUT keep in mind, they eventually reach 2 feet (plus or minus a few inches). Eventually you WILL need a huge tank. either that or keep them until you can't and then give em away/sell em