1) That depends entirely on you and your skill in said technique. None of us can say "THIS, THIS WILL LET YOU WIN 100 percent". Most will say fencing, others kendo, some wushu or Tae Kwan Do. In short, no one can answer this question. There is no zero sum game in martial arts.
2) No martial art actually wants to prolong a fight. Most duels would only last a handful of moves and with little fanfare. If you want a fight to be "dramatic", why not choreograph a duel?
Hmm, true, but I'm wondering which works the best in this situation, me in a surprise duel with someone who presumably has no swordfighting experience, but is much stronger than me physically. I'm also sort of hoping for something that involves the use of only one hand, since I would assume that it's easier to maneuver the saber with one hand on it as opposed to two hands.
Choreography would imply that the friend has some prior knowledge about the duel, which I don't intend to be the case (also, with choreography, the winner is pre-determined). I'm given to understand that people appreciate gifts more when they're surprises

. I suppose I could do a surprise, "real" duel, and then afterwards film a dramatic "reenactment" for the internet...
(I was about to ask how all the Star Wars characters made their duels dramatic without choreographing it, but then I remembered that Star Wars was just a series of movies XD).