Exactly - this situation is the one the screw was provided for. It'll give teh wide area a sort of drum-like tautness, that will suspend you. If you are sitting far enough back, your sit bones should be able to find a nice wider perch to be on.

One problem often is that the rider slides forward off of the wide area onto the narrow area. This can happen if the tension is low and the "hammock" is too saggy, or if the saddle is not tilted up enough for you. Recommendations are generally of two types: "put a carpenter's level across the top, make it level, and never deviate from this" and "make small adjustments in tilt to optimize the saddle's long-term comfort," which IMHO makes a lot more sense.

A corollary to this latter one is to make small adjustments in the saddle fore and aft positioning by sliding it forward or back on the seat rails. If a rider always slides forward during a ride (off of the proper support area) and the adjustments are pretty good, it could be that your natural riding position is just a little forward of where the saddle is placed. In this case see if moving the saddle forward to meet your sitbones makes it better. If you begin to feel pressure or bruising at teh back of your thigh due to hitting the wide part of the saddle, it's too far forward.