Denny,
The assymetrical 2 posts are the way to go for working on vehicles as you can pull the tires and work on the suspension.
As far as mounting points, they have anchor plates that distribute the load wider out than just the footprint of the post. The lift manufacturers will say 4" of unreinforced concrete will work. Hey, you figure the footprint of 4 tires (basically the area of your handprint) is holding your truck up on your concrete floor now....
Finally, before you buy, look at the Mohawk brand--nice lifts if you have the dough. The Rotary's, Bend-Paks, etc. are next tier from what research I have done a few years back.
