Sizing is difficult with brands you don't have experience with. Below is a general chart I use. Look below for an some thoughts of how the shoes generally fit, or ask me for advice. Your experience and preferences may differ from mine.
Edward Green sizing:
Edward Green sizing is quite consistent though the various lasts. Quite similar to other British makers, but sits a little closer to the foot than Alfred Sargent and Loake.
I have personally developed the last we use with Santari, to offer an elegant shape with comfortable fit. There are a lot of great makers today with narrow and slim lasts. I wanted to offer something different. A roomier toe box that fits close to the foot and around the ankles. Comfortable without losing the elegance. Instep is normal, and we are able to adapt this on orders if necessary. Compare it to Edward Greens 202 and 606 for a reference.
Miyagi Kogyo sizing:
Miyagi Kogyo fit will differ from type of shoe. The work boots are quite close to the Barrie and Trubalance of Alden, in D-width I'd say. The formal shoes are a little narrower with low instep. You may take same size as Edward Green, while some with wider feet or high instep may need to go up half a size.
Alden and comfort goes hand in hand, with sufficient room for the toes on most of the lasts. Barrie and Trubalance are both great in this aspect. Aberdeen is a little narrower, and I would recommend going up half a size compared to Barrie. Many clients of mine use the same size as UK makers like Edward Green and Crockett & Jones.