Good description of the armed good guy and the armed bad guy to the 911 operator.
Remember that when LEO's arrive on the scene they don't know who is the BG and they are going to assume that everyone envolved, including you, are the the one's doing bad things.
If time permits have your weapon in as much of a non-threatening condition as the situation permits. If there is still a possible threat holster your weapon or have it nearby, but don't have it in your hands. If there is no more threat, as soon as you hear or see LE lay your weapon down and step away from it. If they respond before you can disarm yourself, hold the gun by the bottom of the grip or the slide. Don't hold the weapon in a manner that you can still use it. As soon as LE arrives stop aiming your weapon at the BG.
Follow all directions of the LEO's exactly. Move slowly, and keep your hands visible at all times. If you put your hands anywhere the LEO's can't see them, they are going to assume you are going for a weapon. Don't argue with them, or try to tell your side of the story until the situation has been neutralized.
As far as any statements go, I'd suggest tell them the basic story of what happened, and that you were acting to protect yourself or others against a lethal threat. They're going to question you, and if it's not a clear cut case of self defense the questioning will probably get a little intense and at that point I'd ask for a lawyer.
Above all, to make yourself appear like the good guy... be the good guy. Stay on your side of the law.
Personal story: Had a person that was up to no good on my property one night. They weren't doing anything that warranted me pulling my pistol, buy I had it on me when I intervened. Before I did so I told my wife to call 911 and tell them an armed citizen in civilian clothes was on the scene. The person left before LEO's arrived, so as soon as they left I handed the gun to my wife and told her to put it on the bed. When LEO's pulled into the drive way I kept my hands open and visible, and told them I was no longer armed. They took a statement and that was the end of that story. Had I kept the gun on me, it wouldn't have been that easy.
Just remember that if you are not LE, then as soon as LEO's show up on the scene, let them do their job. Don't try to do it for them.