Juicy and well done are two words that don't normally go together. However there are many people out there that want their Burgers Well Done.
If you cook it as normal, sprinkled with a little seasoning and grilled until dead, they will get a very dry unpleasant experience. So when someone asks for Well Done, No Problem. Do not season as normal, you need to baste their Burger to replace the juices you are cooking out. Not with a sweet baste that most people might grab for ribs but something that won't take away from the burger experience and also give the seasoning left out. For this I simply baste with a 50/50 mix of Worcestershire sauce and Soy sauce. You start out with a raw patty on the grill and only start to baste after it has had it's first flip. Flip again when just about done and baste again.
Everyone needs to enjoy the food the way you intend it, but to their own idea of what is an acceptable internal temp.
How do I shape my Burger patty?
When shaping your Burger patty leave it much thinner in the center 1-1/2". This will allow the burger to stay flat and fill in the void instead of forming an upside-down cup on your grill.