jsilvas: welcome to the forum. You really should post this to the Coin Forum, so that more people will see your question. However, to answer you: 1) the large 8 is above the first 1 in the date, all other varieties, the 8 is level or below the first 1. 2) I do not know what yuo mean by overstrikes, especially for bust half dollars. There are common clashed dies. Good luck.
