I’m going to link a comment I made last year that helps answer your question. The short answer is: I find they run pretty much true to size.
This isn’t exactly what you asked for, however I think it can be useful. This is my 11N Myers boot next to my 11.5R composite toe work boot. My work boots are built for tough work with thick leather, heavy sole, and as I mentioned a reinforced toe (which adds even more bulk to the boot. Comparatively, my 11N isn’t that much smaller than my heavy duty work boots. I don’t think the narrow Myers boots are that narrow, actually. I’m sure yours will look fine. If you’re still worried about it, may…