"I spent a few hours fiddling around with L5 and L6. At some point I got completely confused following different instructions and ended up with a complete mess.
However, eventually I succeeded and even though I'm not 100% satisfied yet, it behaves way better than it did initially. The pitch knob now does what it's supposed to do (or at least what I expect)" - madigan
IMO this is pretty much par for the course when tuning the EW. But if you haven't make it to the stiff drink step then you haven't put forth enough effort! ;-)
A scope takes a lot of the guesswork out of it and puts you quickly in the ballpark, but it sounds like you are probably close, and Thierry knows this better than probably anyone on earth, so I would follow his advice.