I was non-select in July, but didn't find out until after the deadline for submitting for August had passed. But from my experience, as long as your OR knows you want what you can get and you're not giving up, then reapplying should almost be immediate. I've told my OR to put me in for any URL board that comes up, and to keep putting me in until he thinks the package needs to be changed (new ASTB/new LORs/new required documents, etc) or I am PRORECCed. In fact, the current plan is to be submitted for the October boards before I find out about the September boards, just in case.
The commission is more valuable to me than community, so if it comes to it, I'll have my OR start submitting to me RL boards as well, but I hope it doesn't come to that...