Both of my mmorias are A lasts (not AA which are flatter). They are roomy but not so much that I feel the need for an insole. That said there ain't much stretching gonna happen with that cordovan if they don't fit. I almost went with a 42.5 but settled on a 42. I'm glad I did. Pretty sure they would have been too big.
One note: I find my mid boot much more comfy to wear in general due to the fact that the regular shaft rubs against my right ankle if I lace them too tightly. It's an easy fix (just loosen the laces) but it is a drag nonetheless. I keep waiting for them to soften up but I think it might take a few years. Lol.