Hi Jill, There are at least two schools of thought:
1. Decide on the most accurate spelling and use it as a standard. Most people adopt this course of action almost unconsciously. A standard spelling for a tree presentation is quite acceptable. Provide for spelling and orthographic variants in an opening notes section below the names.
2. Change nothing, using only archival original surname spellings. This practice has one advantage: that one is not tempted to confuse two independent lineages with one another, a danger of standardization. The advantage is worth remembering even if you elect to standardize names for those people who are inside the family tree, i.e., examine the individuals, case by case, before standardizing the surname. You do not want to include all the strangers whose names merely resemble the standard, but are, in fact, of no connection.
One learns by doing, some one will object to what you do post. I suggest you limit tree posting information to deceased people to protect the privacy of all living people and to avoid annoyance to yourself and others. When in doubt, make a note on what you have done to record why you have standardized. Good luck! Aldo