paneling tools: variable grid offset

Hi Everybody,

I am very new to grasshopper and PT. What I want to do is create a simple paneling pattern on a reverse cone surface (now created with grasshopper, but could be any surface). This paneling consist of an outside grid and an offset center grid. But what I want is the offset grid to be variable in offset distance. So I would like the rows in to the top of the surface to have a decreasing offset distance. 

Like I said I am new to grasshopper, but how would I proceed to get this result? Thanks!