I wear size 16W tennis, 15W Magnums fit great.  Perfect fit from day one, no break-in.  Very light weight, excellent for long distance hikes in nasty terrain.
Cons - they wear out fast.  The soft soles wear a lot faster than other harder soled boots, but then they also grip rock exceptionally well.  Price is reasonable enough that I figure they are a good value lasting 15 to 20 days of crazy nasty rock hiking wear, 3 or 4 times that of medium hiking per pair until they are shredded enough that they are ready for replacement.
Still the best fitting boot I know of.  Redwings and others last longer, but always suffer with the fit, and you pay for it with your wallet and your feet.
Forget about idiotic 'wearing in' of high dollar boots, these and other Magnums are 100% on day one.