I'm a mild over-pronator as well. I used Saucony Pro Grid Guide 7's for my last marathon, used the previous version for my first marathon.
But an alternative could be to stick with the shoes you normally use and try to put a pair of Superfeet (Ive got the black ones) in them. I saw a couple of pictures of me doing Park Run this week and my feet and legs were landing totally square coming down a hill at speed, which is not normally the case! You can also try them out for 30 days and send them back is they aren't helping