Stability is definitely the key, but stability also implies consistency over several months. Just checking your water for a week and saying, "Yup... I'm stable" really doesn't tell the story. A new tank will really go through many different stages over the first few months.
In addition, if you're going to adjust your Ca
levels from whatever they are now, get that going BEFORE you add corals. You will, as we all did, try to "tweak" something and end up throwing everything into a mess! It's much better to do that, and learn what you did, with just fish in the tank. Even better would be with nothing in the tank, but I'm not sure any of us are THAT patient!
So my answer would be... give it two or three months or so of stable water readings.