Overshoe sizing question

[Arch]

I'm thinking of getting some overshoes for the next YACF night ride, as my feet got quite cold on the last one. I found these on CRC:

http://www.chainreactioncycles.com/Models.aspx?ModelID=19807

They only have 5.5-6.5 size. My feet are normally 5ish. My shimano M 021Y shoes are apparently EU 39 and US 6.

Comments on the overshoes suggest they are tightish.

Will those on CRC be way too big?

I don't wear overshoes all that much, so I don't want to spend loads.

 

[potsy]

I know with mine(Shimano ones) I went up a size and am glad I did,the tighter they are the more chance of damage whilst trying to get them on/off.
Great things to have though.