General recommendation is to stay with same size as Alden Barrie (so, 1/2 size down from Brannock) on 2030.
Two exceptions come to mind:
1. you have a low-volume foot.
2. you like putting shoes that are too small up on the marketplace.
The 110 and 310 are far roomier (EEE/E) and I could see going down a full size from Brannock on those for some people *if* your foot is slightly shorter and low-volume. I tried to go a full size down on the 110 and the pressure on the vamp...