Lap is stronger if you need strong and don't mind the non smoothness. Most body work is butt weld. Lap is easier to do and no tight matching involved. Up to your desired "look" of it. You will probably not like the lap look. Butt welding should be butt tight.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
| 
