Best place to utilize the jack

So I had a friend help me change a tire on my 68 Dart and he put the jack on the pinch weld. I don't really like that because it damaged the pinch weld a little and when I tried to straighten it, it left a mark and is really hard to straighten because that metal is really thick on the pinch weld.

I didn't tell him I was kinda pissed about it because it would seem like a such a small thing to most people, but just confirmed to me why I do everything myself with my cars and don't even trust shops.

then I started looking under the car and thinking where the best possible place and strongest point is. On the front, it's easy, there is a huge chunk of flat subframe that seems logical but I am thinking about those times you need to get the jack in from either the front or rear of the car, So is the K frame a good point??

where do you guys place the jack ??