I don't BBQ burgers all that often, and didn't do a great job (no pics either I'm afraid).
I used all the right ingredients and tried to follow your tips, but wasn't sure whether to leave the grill lid open or closed during cooking. I preheated the grill to about 450 degrees, and started with the lid open but ended up keeping it shut most of the time, which I think was a mistake. The burgers were definitely overdone at around 6 minutes per side, but luckily still edible.
What should I do next time? Lid open or shut? I was just concerned to see the temperature drop off so fast that they wouldn't get done in the center without longer time on the grill...