Who do I think I am?

I have been wanting to do DNA testing for awhile now.  Last week I ordered an Autosomal DNA test from Ancestry.com which I will take and mail back this next week.  In an effort to make an educated guess about the outcome I have made a list of my 32 GrGrGr Grandparents(all but 2 of them are known surnames)

Paternal Surnames:  Cook(e), (Last Name Unknown wife of Cook), Putman(Last Name Unknown wife of Putman), King, Upshaw, Manire, Jackson, Jakes, Harger, Morrow, Sutton, Frizzell, Kennedy, Manley, Frizzell.

Maternal Surnames:  Luna, Lennox, Rigsby, Lewis, Pitman, Hatfield, Adcock, Bowles, Acuff, Curvin, McElroy, Webb, Hale, Elzie, Hitchcock, Fleming.


I examined the last names and determined from which part of the world they came.  The break down is shown below.

Area	#	Percentage
English	22	68.75%
Scottish	4	12.50%
Irish	2	6.25%
Austrian	1	3.13%
Manx	1	3.13%
Unknown	2	6.25%

I multiplied the amounts by 3.125(100/32) to get the %
I realize this is somewhat flawed not just because I don't know the ethnic background of the two unknowns but in most cases do not know the ethnic background of these GGG Grandparents mothers.  My Hatfield's mother was said to be Cherokee(I don't think her mother could have been more than 1/2 ) but I have no way of knowing how much so I didn't take that into account since her father was an English Hatfield.

I am not sure how Ancestry has their grouping now...but to me looks like I am 90.625% British Isles.  When I get the results I will post them so that I can compare to my guesstimate.  Too it might also depend on how much of each of the genes I received.   Those aren't always exact even in siblings.