ReCreate Rows and Columns of Data Matrix after Grafting tree? Can't interpolate curve through points

Hi -- I'm having trouble interpolating a curve through a grid of points because the data matrix was eliminated after the tree was grafted. Is there a way to re-establish the data matrix of the grid? Here is what I have done so far:

I'm building an attractor point definition, so I started by modifying Davids definition that I found here http://www.grasshopper3d.com/forum/topics/multiple-attractor-points...

it now looks like this:

the resulting geometry looks like this:

 Ultimately I want to be able to interpolate a curve through the center point of the circle that look like this:

but before I interpolate the curves through the center points I want to offset the center points in z based on the diameter of each circle, which looks like this:

now this is where my problem begins. I can't interpolate the curve through the points in the way I stated above because the data structure has been grafted which eliminated the previous data matrix. Is there a way to re-establish the matrix so I can interpolate a curve through the points in the way I want to (9 parallel horizontal lines)?

thanks

-Bret