Both these positions are as I suggested in the other jacking thread - fronts on the triangulation at the bulkhead corners, and rears under the spring hanger and set belt mount crossmember.
But to raise the rear, you'll need two jacks if you want to use those points to lift. I wouldn't do one side and then the other - too much twist on the chassis. I'm not too keen on using the diff housing, as its a long way under, and can slip easily unless you have a cupped jack pad, and you'll need a long reach jack. It also puts a load on the diff casing joints between the tubes and the casing. So for me it's safer to use the rear crossmember. At the front, there's limited space to jack in that spot and then put axle stands in the same spot. Given that the weight of the car is taken by the front crosshead, it's more than capable of taking the load when jacking up.
Just be very careful because they can slip, and you can do untold damage if you get the jack in the wrong place.
