[pmax]

Using the factory jack holes, you want the jack at an angle, not perpendicular or parallel to the chassis, as the PP article shows ...

https://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/01-Jacking_Up/01-Jacking_Up.htm


and discussed here http://forums.pelicanparts.com/porsche-911-technical-forum/1144744-car-slipped-off-jack-stand.html.

As to the front, here's a fun read
https://forums.pelicanparts.com/porsche-911-technical-forum/889148-how-do-you-jack-entire-front-911-once-center-jack.html

Stay safe !