The only surefire way for an artist to correctly announce a song's RBN release date well in advance is to get very lucky. The signs point to Harmonix not holding songs in quarantine any longer than they need to be. Right now the quarantine system is designed for a final inspection of content (and legal clearance if necessary), and it's not set up with timing releases taken into consideration.
Rather than announce a date, an artist might want to announce that it's "coming to the RBN soon," followed by another announcement once it gets put up in the store.
Yeah, that would work for some situations. I'm just saying it'll be hard to do something like put out tracks from a new album on the same day as the release. For my money, the best bet would probably be to get the tracks into playtesting a month in advance and stay on top of it with any fixes. Optimally you'd get it into peer review a week away from your expected release date and pray you don't have anything major to fix. Then you gotta hope you get your 8 reviews in that week.
I Am King Tony - "Stereo Stereo" available on RBN!