Rostock geometry

Hi,

I am trying to set up my Rostock in the modified Marlin firmware, but my geometry is slightly non standard*. In configuration.h DELTA_SMOOTH_ROD_OFFSET refer to the distance from the center of the build plane to the center of
either:
A) each smooth rod.
or
the mid pint of each rod pair.

* I used the screw hole for the Motor end and idler end as the smooth rod positions Duh!

Mike