Jennies

I got the preferences for my sockapalooza 4 pal. http://sockapaloozafour.blogspot.com/

I´m a little bit confused...
My sockpal´s foot is about 9" long (somewhere between US shoe 6.5 and 7).

If I convert 9" into cm, I get about 23cm. That will give me european size 35.

But, if I use this http://www.i18nguy.com/l10n/shoes.html#adult 
to convert the US size into european size, I get that it means european size 37/ 37.5
I think, I will go for the european size 37.5  

What do you think?

I´m planning to knit Embossed Leaves Socks http://www.favoritesockskal.blogspot.com/ 
for my Sockapalooza-friend.
My pal wants her socks to be machine washable....  she lives in the USA (Eastcoast).
I think that the weather over there is much warmer,
than up in the north of Sweden where I live. So no wool...

I went to my LYS and they recomended "Tilda" 50% cotton, 50% acrylic (150m / 50g).
I will cast on later this evening at the local library´s Knitting-cafe. 

My sockpal likes green... so I´m going to knit, with some olive-green sockyarn.