On the subject of abbreviated names versus full names, what Kate has said is correct.
Just to add to that reply, what some people are doing is expanding the given name even when it is written as an abbreviation in both columns. My understanding is that you write the fullest version of the name that appears. If both columns are written as 'Wm', then you key 'Wm' not William.
If my understanding on this is incorrect, please let me know.