I'm not a lawyer, and I'm probably not one of the 12 that would be sitting on your jury, so take what I have exactly for what it is... My opinion... It's not advice or any of the such... Simply an opinion...
First off, TECHNICALLY speaking Delaware doesn't have a brandishing law. With that in mind, TECHNICALLY speaking drawing your weapon isn't a crime. Now if you draw it and point it at someone, or draw it and start yelling that you're going to shoot someone, well then that falls under other laws like terroristic threatening, etc...
However, (if there are witnesses
) if you drew your weapon and things escalated it could be surmised that you in fact escalated the situation. That would completely be up to how the jury interpreted things.
Also remember that in Delaware UNLESS you are INSIDE your own home, there is a "Duty to Retreat". Meaning that your first course of action would be to get inside the house to prevent the encounter. Now if the guy busts in once your in the house, then it's easy to feel that you are in danger of death or serious injury meaning you could then draw and/or use lethal force and not have much trouble.
If the guy hits you then it's really debatable rather you could use lethal force. If the guy was built like Tyson and you felt he could easily kill or seriously injure you, then again it shouldn't be hard to be considered justified. On the other hand if the guy is 5'2" and scrawny and YOU are built like Tyson, then you might have a hard time convincing anyone of that.
On the other hand, if he produces a weapon, then you can easily surmise that serious injury is inevitable, and again would be justified.
One last note. The reason you are still probably a bit confused about "when" you can draw your weapon (and use it) is because in general an instructor is not going to give you hard set rules about when it is or isn't acceptable. Why? Because there really are no hard set rules. Yes there are laws about what DEFENSE you can use for using lethal force, but again that's interpretable. It depends on rather they decide to prosecute and if they do, it depends on what the jury believes you "THOUGHT" during the situation. There really is no right or wrong answer in these "grey" areas... All you can do is use your best judgement based on the law and hope that others decide that your judgement was sound.