I have a question regarding the "no instant FTL" rule and how it relates to wormhole-related mechanisms. Presumably a direct window-style wormhole isn't allowed, but if the wormhole instead opens a "tunnel" that one must traverse between the two points, just how long does that tunnel have to be? Where do you draw the line between "effectively instantaneous" and "acceptable travel time"?

I mean, a wormhole tunnel that stretches five feet is technically not instantaneous and requires you to spend however long it takes to move five feet to get from point A to point B, but that seems like it'd still be unacceptable.