(facepalm) - The Cervelo R5CA was designed to be ridden without need for a setback seatpost as a way to further its lightness.

From Cervelo's website:
"This means the R5ca with zero offset post fits exactly the same as any road bike with 73 degree seat tube angle and traditional 25mm offset post. "

Anyway...
I have to agree with reading the Peter White article. It really is pretty good. It's probably best suited for someone who understands their bike fit and just needs a little help really dialing it in.

One thing to keep in mind is that saddle setback does two kind of competing things to your fit, one of which has been brought up but the other I don't think has been. First, having your saddle sufficiently far back should support your weight such that it is easier either to get low or utilize your drops. The second and competing thing in my opinion/experience is that sliding your saddle back closes off your hip angle which may restrict your pedal stroke over the top.