"Match the force" is extremely broad. If someone tries to beat the shit out of you with their bare hands, and you defend yourself with a baseball bat, that's almost certainly going to be kosher. It doesn't have to be exact.

Failing to use proportional force has to be really egregious to meet the standard. Something like shooting someone who was twenty paces away from you and armed only with a tire iron (even then you might still have a case). That's a situation where any reasonable person could have defused the situation by just telling the other guy to fuck off, or get down on their knees with their hands behind their head. And even then, you'd probably still be OK to shoot if, say, they lunged at you (check with a lawyer before putting this advice into practice, obviously).

Basically, if you can make the case that what you did was necessary for your own safety, you're in the clear.

The other stuff that gets people jacked up is continuing to "fight back" after the threat is over. You hit a guy with a baseball bat, he goes down... Yeah, that's probably kosher. If you were afraid for your life, well, you did what you had to. But if you then proceed to beat the guy until his skull shatters... Well, what part of that was necessary?

No one has to think through the tests described in the law, because those tests simply exist to define what everyone can already intuitively understand as being reasonable behaviours. You defended yourself? OK. You hunted the guy down and tortured him? Not OK. This isn't complicated, and it's not difficult. You just have to exercise a modicum of self-restraint. And the cops look very, very favourably on people who were defending themselves, unless there was clear evidence that they either majorly crossed a line, or they were actively looking for trouble (ie, walking around armed for a fight).