Requesting a Time-Out after a made basket

[PGCougar]

In general I think I understand the rule that you need team possession to call the time-out, unless it's a dead ball situation. Usually in late game situations, the team from behind will try to call a timeout right after the make. With my teams, I've usually instructed the players to call for Time as the ball is falling through and, if the situation permits me, I might try to let the official know I'll be calling it right after the make.

Question is this. Assume Team A just made the basket. At what point is Team B in possession? Assume player B5 grabs the ball as soon as it's out of the net, and it takes about a second or so to get behind the baseline. Does a call for time by team A get granted in that period? How late can such a request be granted?

I'm not as good at navigating the rules and case books as the rest of you, but if you could point me in the right direction, I'd appreciate it.