I’ve just been through all of this and have had 3 sizes of each brand come through my front door. For me, and of the ones I tried, specialized were the narrowest, followed by lake mx176, then Shimano standard width then northwave, lake mx238 were great but the heel would lift, the winner was Shimano wide fit xc701 bought from bike24 in Germany as we can’t get wide fit in the uk. Quite a few people told me not to even bother trying giro and fizik. It’s interesting digging around on the lake website because they have a matrix that goes into serious detail. It shows that although the 176 and 238 are both wide, the 238 has more volume. Shimano also have a comprehensive table showing their different lasts. It helps to know where you foot is wide, mine is very wide around the ball of my foot But my feet are small. Good luck and I hope this helps. One last thing, for the first time in however many years, I was able to buy the right length shoe to get the right width and it feels so much better not having all the extra space in front of my toes.