nobody can tell you whether you are on the right track or wrong track because the question is vague at best. and since there is no standard for brainwallets i would be surprised if using it would work. for example this one that you linked is doing a 1 time SHA256 on the passphrase, i have seen others do different numbers of hashes, or even using HMAC functions or use PBKDF functions and use your passphrase as its seed with 2048 iterations.
each of these methods would give you a different private key and without a starnard who is to say which one you should use?