Are you saying that you need to tap the block? I did not get that impression when I read the TSB. I was under the impression that I would only have to drill the hole in the valve cover.
The place where I am seeing the leak is in the area where the valve cover gasket is missing one of the screws (the bottom left one). I was planning on pulling the cover completely off and drilling holes (after saying a few prayers), and replacing the gasket and putting it all back together.
I too am a member of the leaky valve cover gasket club (Only the left cover is leaking, I guess I lucked out!). I am following the steps outlined in the TSB. Any idea on how to detach the wiring harness around the valve cover? Any secret tricks? Looked around, but nothing jumped out. Thanks...