Personally, if I'm doing something needing stands I jack it using the front crossmember point and the diff. Then the stands go under the jacking pads. That way I'm only jacking twice, not four times. The only time I jack it up using the jacking pads is if I'm only working on one wheel, like a puncture or such, in which case I'm not going under the car and won't be long. Or if I'm going to be a while and the car is going to be up for any period of time, then I go back to jacking the whole car up, even for just one wheel. If I really have to (because stands under the jacking pads would be in the way) I'll use the k-frame near the bolt points. The k-frame is still pretty strong as it has to be. Though you'll see the front jacking point is still stronger than the rest of the k-frame, so I try to not use any other part of it. I wouldn't use the middle of one of the k-frame members, even though I doubt they would bend. But I'm a bit paranoid.