Osprey,
I go one size larger for the boot unless the manufacturer states that the shoes are made to accomodate wader sizing or you are going with a 5-mil thick wader (up an extra half size). Also, I've owned and worn out 4 different pairs of wading boots (all Felt non-studded) over the last 9-years. I'd stay away from the synthetic leather models. Even the boots made from this over a 100 bucks crack and deteriorate far too soon for the money. Danner makes by far the best boot (in my opinion) on the market. They are very comfortable, lighter than many models, and wear well (The stitching must be coated with Aqua-Seal before use---the only weakness). I have a pair of the 8-inch river grippers (non-studded since my little hypalon boat hates studs) and several friends who guide year round from Alaska to Patagonia and swear by them. They run about $145 in most catalogs, but REI had them on sale for $115 OR you can get them at the Danner Factory Outlet in Portland for $100.