the newer mizuno model 9 are a bit wider so i went with half a size smaller. my wave drive 8 are in 26.0JP/40.5 and weigh 275g... and are they true to size or similar to #8? I use EU 45 in #8, which means I have a full width of my thumbprint of open space infront of my foot in the shoe, just to make sure they are not too narrow. The weight of them are 330 grams.
If I measure the widest part of my forefoot straight across, I get 11 cm (4.33 inches)