Basing on the Jedi approaches we see in the movies, it seems the Jedi policy in dealing with dangerous enemies, like Siths, is attempting to arrest them, not necessarly engaging in a fight-till-death, but just enough to get them captured.
So it seems that Jedi are instructed to use a defensive fight style, instead of a mad rage attack, which would keep them from the anger of trying to kill someone to just engaging enough strenght in battle to imobilize the foe.
- EPISODE II (Obi-Wan / Anakin vs Dooku)
Obi Wan: We move in together - you slowly on the left...
Anakin: I'm taking him now!
Before Anakin's foolish attack, Obi-wan, as an experienced Jedi, intended to use an slower defensive approach, which he mantained during this battle.
The same as Yoda did when entered this same battle. He kept defensive until there was no way but to fight Dooku.
- EPISODE III (Obi-Wan / Anakin vs Dooku) (again)
Palpatine: Good, Anakin, good. Kill him. Kill him now!
Anakin: I shouldn't...
Palpatine: Do it!!
Palpatine: You did well, Anakin. He was too dangerous to be kept alive.
Anakin: Yes, but he was an unarmed prisoner. It's not the Jedi way.
Anakin's and Obi-Wan's instructions were primarily to arrest Dooku as a prisioner. Although Anakin let himself be carried out by rage, he knew that a Jedi is suppose to use just enough strenght not to kill, but to capture.
- EPISODE III (Jedi Council meeting)
Anakin: A partial message was intercepted in a diplomatic packet from the Chairman of Utapau.
Yoda: Act on this, we must. The capture of General Grievous will end this war. Quickly and decisively we should proceed.
Again, the main Jedi policy when dealing even with the most dangerous enemies is to arrest, not kill.
- EPISODE III (Mace Windu (and other Jedi) vs Palpatine)
Mace Windu: In the name of the Galactic Senate of the Republic, you are under arrest, Chancellor.
Palpatine: Are you threatening me, Master Jedi?
Mace Windu: The Senate will decide your fate.
Palpatine: I am the Senate!
Mace Windu: Not yet!
This is the one I believe best example the point. The Jedi approach was aggressive, they went for battle, with their lightsabers engaged. But not to kill, in rage, but to arrest.
Here's where I believe there's the balance:
Is there a proper approach, as a Jedi, to defeating a Sith in battle with minimal risk of falling to the dark side yourself... without appearing like some pacifist coward who always run from battle waiting for a nonviolent solution...?
Yes, a defensive fight, meant to neutralize the opponent, not kill it.