We didn’t have versa hubs so we did something similar, but could do it more efficiently by attaching the lock bars to each other through the wheel.
12T pinions work as well friction fit. They kind of make the flex wheels expand to be a bit more hexagonal, though. Heavy too, but works in a pinch.
though your method is easier and lighter, the standoffs would be able to move in the flex wheel’s gaps. My method also slightly reduces insert slop/backlash. 
That does sound theoretically better. We didn’t have any issues when we used that method, if anyone is wondering.