Re: Silly question...
I am not sure what the RRS in Canada require. In the US you mixed a couple of terms that don't have a lot of meaning, and I am not sure what you are describing.
In the US:
If you passed a vessel from clear astern, then until you have broken the overlap you have no right of way.
If the overlap was broken within three boat lengths (of the longer vessel) of the mark then you are still the burdened boat.
If the overlap was broken before entering the circle, then it also can't be required once inside the circle
If you had right of way, then you do not have to give room at the mark, and can tack at the mark. The rules don't require it, but in everything but the most aggressive fleets call out to the other boat that they have no rights and you are tacking. This will help to eliminate collisions.
How far will I push it? It really depends. On a Wednesday night beer can race, not very far. But when we were racing for the Lightning North American Championship, I would have happily demanded every inch of my rights. But here every competitor that was in the top of the fleet was also well aware of the situation as it developed, and would be prepared to duck anyway.