What to get with Brannock 10W on left foot and 9W on right?

This is a bit unusual, but recently got re-sized on brannock and my feet are a whole size apart. I know the smart thing to do is to go with the larger size, but I'm wondering if you have any advice on how much to size down. Is a 9.5D reasonable? What about EE width? I don't have a store near me so I can try them on (but I can return and exchange online orders) so I'd appreciate any help. Thanks.