In the front--catch the back edge of the crossmember but be careful not to have the jack pad too far to the rear--the oil pan is close. If you can't see the crossmember edge you can jack the car from one of the regular jacking points a bit with the car's regular jack to get a better look. The jack stands can be safely placed under the car's jack points or under the ball joints or along the back edge of the control arm -- depends on what job you're doing.
At the rear--it's perfectly ok to lift the car from the pumpkin center. Place the jack stands under the car's jack points--or--up into the trailing arm with the pad facing front to back placed under the trailing arm bushing (the large one directly under the axle shaft). Do not place a jack stand along the length of the trailing arm - very unstable there. -- Dave