The spin boat wouldn't be dousing within the 2 length circle. The douse would have started much earlier than that and, if timed properly, would be finishing up as the boat gybes. You can make a decent rounding gybing around the mark (or within one boat-length of the mark) but it takes some coordination and practice. Spin up or down makes no difference to the rules situation.

I use this maneuver quite often to try and hold an advantage and it usually works if the gybe-douse is clean.