Understand folks believe it is dangerous to get under a car supported on floor jacks. Yes, hydraulics can fail. However, in my 35yrs of being a shadetree and having owned many floor jacks, I've yet to see one fail catastrophically. One of the 2-ton HF floor jacks did finally develop a very slow leak, after working in my garage for some 20yrs. So I replaced it with a brand new HF 3-ton low profile HD floor jack.
These days, I have no problem getting under my car supported by two identical 3-ton floor jacks. I do place a 6-ton floor jack right next to each of the floor jacks. The telescoping supports are extended right up to the car's under body but not bearing any weight. They are just there to catch the car, in case the floor jacks fail. Obviously, the jack stands are not placed under where the designated jack points are, but realistically, in the unlikely event they are ever called into service, I could care less what that does to the car's under body, as long as they keep it from coming down on me.
To me, doing it this way is more efficient and arguable safer than trying to jack the car with a single floor jack on some center point, in order to place two jack stands on the pinch welds, then having to repeat the process to put the car back down.