Sorry, but I forgot to mention the most important. I have changed the setting 'Monitor autodetect' in the customer service menu to 'No' in order to make the autocontrast work with the Panasonic. Shortly after this change I got the message 'Safe mode' on the screen but after resetting the BS3 this message dissapeared. Maybe you can try this to make it work.
I also noticed that the screen became darker but at the moment I'm doing some tests with the BV9 autocontrast sensor which is more sensitive in my opinion. It looks better but now I have to build this sensor into the existing BV5 holder.
BTW, I'm building my own BV5 HD or a 'baby' BV9. I ordered a lot of BV5 spare parts, bought a broken Avant using the motorstand and speakers/amplifiers, a Panasonic D9 and a BS3. Everything works but I still have to make my own +/-20V power supply and a delay circuit to make the center speaker work without the 'plop'.
Still some work to do...