If the narrow is too tight I would just go up a width.

Don't forget your feet will splay out more when you stand up and put your full weight on them. The more you weigh the more they splay usually.

I find that I also go down a half size in size with NB if I go up a width fitting so if you on the border of the next size down I would try to get both sizes and return the one that doesn't fit as well.