banzaiburgerThey work for Medium to Wide fittings. We've successfully fit lot of customers who take E's and EE's in these. The original German Army Trainer design was run in whole sizes and intended to fit a large variety of feet. It's a very versatile shape that adapts well.
If you wear an E in something like Alden then you should be good to go. I'd advise buying your typical dress shoe size. We've had a few guys who did not find them wide enough, but they take a VERY wide fitting, and find it impossible to fit into nearly any sneakers on the market.