To visualize different size DP9 blocks, I would get a picture of a full size quilt and then decide how large the DP9 would be - say 24" (using 8" blocks)(8"x3=24) and then blocks off with paper the extra blocks on the picture.
This will give you an idea how the pattern would develop if the DP9 block was oarger than say 9" or so.
Does this make sense?