Hi,
I envy you!!! I can only tell you what I experience when I clean out. It usually starts about three hours before the event when I slowly insert the hose of the shower as deep as possible within me, and let it clean all the shit out. It always feels completely empty afterwards, but I know that there is usually that lingering turd which stubbornly refuses to move for a while. Sure enough, when I repeat the process about an hour or more later, I finally dislodge the last of it, and then I know I am usually completely clean. However, I never trust that first "clean feeling"!!!!!! But then, that's just my body - we are all different, and some react in other ways.
Good luck, and I hope we get to see the pics. When is the big event?