Place the jackstands under the jacks points, which are the rubber cushions under the rocker panels. If the jackstands don't have a large enough cup to spread the load, you can use wood blocks between the jackstands and lift pads. Just use your head and make sure what you rig up is stable.

Always using a wood block on the jack cup, I lift the front end with the cross member and the rear with the bottom of the diff. I belief some have reported damage to the diff mounting lifting the bottom of the diff, but I have never had that problem.

Duke