First, here is how Drake has his kids run the "choice." It is the same concept I described, though he has added a "safety divide" or climb type route by the tight-end to help stretch the safety; it turns it into something like four-verticals from trips, though with the choice.
First, here is the play against Cover 3 with a zone-blitz. The blocking isn't quite there but the QB moves in the pocket and finds the seam-reader (slot receiver). The free-safety here jumps the tight-end on the climb/divide route, which makes the slot wide open. It is actually the backside cornerback who makes the tackle in the end zone, though he is too late.
And the video:
Against Cover 2, where the safeties drop very deep, you can see in the video below where the seam-reader works off the underneath defender and under the safety into the void for a nice completion.
And finally, against Cover 1 man they get a matchup they like and throw the go to the singled up choice receiver (though they don't complete it). The quarterback does a good job getting the ball there before the single-deep safety can get over. On this play they also keep two extra guys in to protect, so it kind of becomes a three-man route.