The best/safest way to get to Petit Tabac is to arrange one of the boat boys to take you, weather permitting.
Respectfully, no. The best way to visit Petit Tabac is to be on one of the three - four boats able to anchor there. To do that, you have to be early. As others have noted, early light may not be best for the south passage. So, safest is the "long" way, but the reward is well worth it.
