Usually, when I use the Norton hone, I use a smaller portion of the stone, and not the whole width. That has to do with experience and habit from using other hones, both natural and synthetic, that are shorter in size. But, I have a theory how a wider stone might prevent overhoning the middle of the blade.
When the Norton hone is it's normal width, 3 inch, what happens is that the tip of the razor spends more time on the hone, and it is on it from the very beggining of the stroke, thus not allowing the pressure to be concentrated on the middle section of the blade. This poses other problems, like preventing the blade to be sharpened evenly, because no razor blade is completely straight, and when the blade is laying on a 3 inch hone, with it's whole lenght, there will be only a small portion of it in contact with the stone. Refer to this thread for more info. There used to be pictures in it, explaining my point graphically, but there gone...
http://straightrazorpalace.com/basic...-pyramids.html
When using a 1.25-1.5 inch hone, the heel and middle of the razor contact the hone first, allowing every part of the hone to touch the blade, and the pressure is more concentrated in the middle, overhoning it. I think what should be done is to force more aggresive X pattern, with a stroke ranging in lenght ot more than 4-4.5 inches, to prevent overhoning the middle portion...
Nenad