If I may put in my 2 cents.
1. any jack stand can fail that is why I always have 3 points of contact. I leave my floor jack in place. I release the weight to the stands then reset the floor jack to just make FIRM contact, not actual supporting contact, but enough so that if there is movement it stays in place. Also provides a leverage point for someone to get the cars weight off you should it fall.
2. You want as wide a base as you can get the taller the jack stand is
3. always place on frim material to support stand that the legs will not sink in to, i.e. concrete or place on a 2ftx2ft or bigger sheet of 3/4 in plywood. Remember pavement can become warm and allow jacks to sink in
As for the 4 ramp trick. It works, but just remember to put axle with parking brake on ramps 1st and then jack up the other axle so as not to have the vehicle roll during the secondary ramp install.
Also you can lay a 2x6 on the ram and set the vehicle frame, etc. down on the ramp if needed, i.e. using it as a jack stand if needed.
Finally, on a more morbid note, lost an uncle that was a drag racer working on his own car due to jack stands sinking in the ground about 40 years ago. He knew what he was doing, and hand done it a million times, but a little snow in East Texas at the time hand softened the ground just enough to cause the jack to shift under load while trying to remove drive shaft retainer clips.
Morale....Never be come complacent when it comes to working under a car. When you do you risk the ultimate FAIL.....