I had a look at your question but you where quicker to post a reply than me.
You may want to replace Brep/Crv intersect and Crv Closest Point with just Surface/Crv intersect as this will give you the t output required for the shatter. Also cull patten may be better than Item unless you want to change it with just a False True cull pattern.
This is just person preference for using least components as possible with the shortest calulation time. As working on some Definitions with 100's of components And lots of sliders.