If you're going to use corn stalk bales, you will need a grain mix that is about 14% protein.  I'd use cracked corn, DDGs or corn gluten pellets, and a good balancer with Rumensin.  Charloais steers are pretty framey, so I'd start them at about 10# of grain mix and work them up to 15# over a couple of weeks, after that increase them slowly (1/2 pound every third day) until it takes them all day to clean up their grain mix. After that just keep up with them as they grow. They will still crave the corn stalks and they'll pretty much eat what they need of them.  Hand feeding them with free choice stalks, I'd say it'll take at least 9 months to get a good degree of finish on them.