I like the convenience of using the factory jack points (holes) but I absolutely DO NOT like using the factory jack - except in cases of emergency road side repair. You all know it can be a little unstable... I solved this problem by using a large heavy duty bolt. This bolt can be inserted into the hack hole and is long enough to safely use a floor jack to raise the car. Only big floor jacks have enough travel to make this work. If you have one you should try this!!
WARNING: DO NOT use this method if you have a rusty undercarriage. Jack points can weaken are are usually the first to go - especially on cars in the salt rust belt...
NEVER NEVER - Work under the car using this method to support it. Always support the car underneath with HD jack stands for safety if you must get under the car. For added safety use a backup (ie like leaving the wheel and tire on the hub so if car drops - it can NEVER drop to the ground.
This is a BIG bolt. The heavy threads keep it secure in the hole and the big head keeps it secure on the head of the floor jack.