OK, the important thing to remember is that if the top cap touches the top of the compression plug, you've failed. The top cap is there to provide preload on the headset bearings.
For those who are not familiar with the Road Logic fork setup: It's an all-carbon steerer with a compression plug that has a top that lips over the top of the cut steerer, the same diameter as the steerer. For this reason, clamping down on the stem will not crush the steerer tube, as it's supported by the compression plug, this is why the traditional spacer above the stem is not required for this setup. The compression plug looks like this:
