>>1959016A little over 40 miles is about my limit for one bottle in warm but not hot weather for a moderate intensity. In real heat I can down a serious sized bottle after just ~20 miles (I don't shy away from the climbs). A century is 4 bottles worth if hot, so either a supplementary bottle on the waist and/or refill stop somewhere.
>>1958985Shimano shoes fit me rather well, especially if the ones you look at come in fraction sizes and they have wide variants too. Very happy with my RC7, the gravel versions (ie RX8) they do should fit the bill. Aside from Pearl Izumi (in Japan its different production than the US brand) I'm not really aware of other Japanese brands for shoes.
M540s are anchors compared to road pedals with carbon but still lighter than some other SPDs while not being stupid expensive. They seem somewhat similar to the M515s I ride.