Brad,  What is your goal with the ripper?  Break up compaction or mix fertilizer in deeper?  The picture above with your chisel would mix in the fertilizer deeper than the inline ripper.  The inline ripper is going to leave a slit in the ground and heave it up a little, but not much mixing.  May be better off finding a mounted chisel instead of the pull type to help with traction, put curved points on it a go.  Or find a tebben, or similar ripper with parabolic shanks that with mix the soil better.

Here is a link to what the inline ripper will probably do.

http://talk.newagtalk.com/forums/thread-view.asp?tid=434926&mid=3491559#M3491559