How done is done???
Ok, a rookie plowing in here now....
I have a friend that worked at a burger house in the past. He told me that one way to tell if a grilled burger was done is to bounce it.
Lift the burger with a spatula about 6 inches off the grill. Drop it and if it bounces it is done, if not keep on cookin....
Actually this technique will give you "well done". No shades of wellness [doneness?].
Another factor that will help is to press the center of a thick burger down to about half thickness. Make a well in the middle. Helps the center cook about the same speed as the outer edges which get more heat. Also makes it level out so the tomatoe does not slide off :]
"If it's stupid, but it works, it isn't stupid."