Nicholas Snow maternal lines name questions

[Abby Glann]

I am to the point where I am working on merging the many Nicholas
Snows, and the Mayflower colonists' grandmother is Elizabeth Rowlles.
I admit I am not incredibly familiar with this line. I know with the
Euro group that as long as there is only one set of supposed parents,
they are being kept linked with a note, which from what I am seeing
for sources, should be the case for MF's Nicholas' parents and
ancestors. All that being said, I am running into a lot of variations
on names for the maternal lines. His mother was Katherine Harwoode and
both Katherine and Harwoode are spelled numerous ways from different
imports. The first name isn't too hard, with the nickname option, but
her last name I am not sure where I should go. Any thoughts from those
of you who may be more familiar with the family as to what would be
the best option? The same problem pops up with Elizabeth Rowells. I
have been using Mayflower sources for the passengers and descendants
up until this point, but ancestors and parentage gets sticky with a
lot of them, it seems.
Thanks!
Abby