Where to Jack up the front on 98 GT?

I wanted to jack up the entire front end with the 100lb floor jack I recently acquired. I've seen several posts that state that many Mustang owners jack up the front end via the crossmember, but I had my jack slip twice last night (thank gosh it didn't fall completely off :what

There is a very small decline where the car is parked (it wouldn't roll if it were in neutral,) and I have the rear tires chocked on both sides. The jack is a 3.5 ton with 21in of lift capability, so that doesn't appear to be the case. I've done a good amount of research, but I haven't been able to find much else when it comes to jacking up the front end.

I do have 2 different floor jacks, I suppose I could jack up each side by the jack spot behind the wheel high enough to get a stand under there, any other ideas?

I did find this diagram,Chad's 2000 Mustang GT American Racer -- Jacking Points , but it seems that the crossmember is the main place recommended to jack up the entire front end at the same time. And yes, I do plan on installing Full Length Subframes in the near future, but not an option just yet!

-Karl