Most suggest waiting two weeks- gives stones time to move forward. For me personally, I get better results if I wait three weeks or more. It is also best to make sure you are completely "recovered" before doing the next flush. If it seems to take alot out of you, you should wait. On the other hand, if the pain you're in is a gallbladder attack, you may want to flush again right away to relieve symptoms.
Nothing is black and white with flushing, gotta just do what feels right to you :)