Personally I would not feel safe with my lug bolts under torqued.
There are two reasons that you torque the lug bolts, one is so that you ensure that they are tight enough that the wheel won't come off, not a good thing.
Secondly, you torque them evenly in a star pattern to prevent brake rotor warpage.
In the early eighties I started just "torquing" my lug bolts with the factory lug wrench. I tighten them in the five pointed star sequence, by leaning on the handle an equal amount in sequence. I have never warped a rotor or lost a wheel with this method.
First snug them in sequence, then put the wrench on each bolt, in sequence, in a position roughly parallel to the ground, then put your upper body weight on it. After using your torque wrench to 75 pounds, you should have a bit of a feel for how much weight it takes on your wrench.