^ you should be a UK 9.5 in Hiro, Ben and Ama lasts. Forget anything below Hiro if you are a genuine US D width. I'd say get a pair of Hiro lasted monks to start with. There's really no telling if they will be perfect or slightly too snug for you. The only way to know is to try them on.
If I was you I'd get them in both UK 9.5 and 10 and then return the pair that doesn't fit. Ofc if you're from the US of A it's a hassle with the returns and also painstaking expensive.
Comments based on personal experience from the AE 5-65 in B width and Meermin New Rey, Olfe and Ama.
Thanks. My 10.5Ds are pretty snug, so I'm thinking 10 is probably the best bet. Return shipping sounds daunting..