Stringer rocker when shaping single to double to vee

Trying to get some clarification on what exactly the stringer rocker is doing when shaping in a deep single concave, to double concave, to vee?  Would I start to shallow out the middle of the concave as I go into the double so the stringer line rises?  Have been looking at the bottom of this board(proctor pipsqueak)…http://www.youtube.com/watch?v=e_-OE_ITgv4

 

at 1:05 shows bottom contour

at 1:39 shows rocker profile with the step rail in back 10"

 

 

I’m interested to hear from some of the pros here on Sways about this one too.

I just shaped a bonzer bottom. single to double within slight Vee…

.02 from a backyarder, maybe showing my ignorance here but … if you have enough foam and can visualize what you want to end up with - IMO there’s no reason why center rocker has to be affected by your bottom configuration.  Center rocker can, but does not have to flatten to accomodate concave. That’s what usually happens when you add concave to center rocker rather than plan your concave with center rocker already established