Hey Dan. I knew Irving pretty well, saw him play numerous times, and we discussed the two rail kick safety in 14.1 on a few occasions.
The extent to which Crane used the 2-rail safety has been overstated by the pool historians. Though he used it in numerous situations, the position from which he typically liked to play it was when he and opponent were both on two fouls and the pack remained undisturbed. His reasoning, as he explained it to me, was that it wasn't such a terrible result if he missed the pack completely and that if he got the safety, his opponent, already on two, would be under great pressure.
If you want to work on something, Dan, work on your opening break safety, which you will be required to play after a third foul. Unless you're very good at it, the percentages for taking a third foul intentionally drop quite a bit.
In all positions in which an intentional third foul is being considered, among the most overlooked points in the game's tactical theory is that when you take a third foul when you and opponent are both on two, if you execute the opening break successfully, opponent is in hot water.
It's way more important to practice your opening break than to learn the Crane safety.