How should you stage the attempt of assassination on banquo and fleance?

According to the text, in this scene, Act III Scene 3 of Macbeth, Banquo and Fleance have returned from their evening ride, have dismounted and are walking back to the castle. Shakespeare arranged this for two reasons: first, so he wouldn't have to bring real horses onstage and second, because mounted men are harder to kill. It is implied that the murderers have picked this spot for their ambush because they know that Banquo will have dismounted. Since there are three murderers, it makes sense that two should attack Banquo and one Fleance.

There are two basic ways to arrange the two groups of actors: murderers upstage and Banquo/Fleance downstage, and murderers on one side of the stage and Banquo/Fleance on the other.

Starting the scene with the murderers upstage centre makes them easy to see and hear. They can be hidden from Banquo who can pass almost under them before they fall on him, causing suspense. Because their attack is delivered downstage, Banquo cannot defend himself without turning his back to the audience, so either he will have to turn away from the attack or be quickly vanquished.

Starting the scene with the murderers to one side makes them harder to see but does give them the chance to attack across the stage. Since they are attacking laterally, the fight can be prolonged without making anyone invisible.

One of the key things to remember about the scene is that Fleance has nothing to say. Banquo, on the other hand, has to be in a place where he can be heard as well as seen. It makes more sense to have Banquo downstage and Fleance up. Possibly the murderer may lose track of Fleance when the torch is dropped (see the line "Who did strike out the light?"), or Fleance may be able to hold him off for a bit. In any case, he must remain onstage until Banquo's line "Fly, good Fleance, fly!" It would make no sense for Banquo to tell Fleance to fly if he was already flying or, worse yet, out of earshot. Fleance must not be blocked by Banquo and the murderer(s) who are killing him.

Timing among the five actors will be tricky. It's a scene which demands plenty of rehearsal.