I honestly think a few pounds of gear more or less makes way less difference than wind strength or direction: a factor that can rarely be planned for if the goal is a certain distance in a day.
Some days you fly, some days you slog.
For me the biggest factor is getting up and away early in the morning, and getting lots of miles in before lunch break - especially if riding in hot weather. I typically wake up at 6 a.m and am on the road an hour later. I love the early morning hours
Yup, on a bike tour where the weight is on my wheels, not on my feet, I am not very careful on weight. Often carry canned foods, etc.
Some days with a tailwind, I reach my planned destination early and then decide to go another 20 miles (~30km). Or days with a strong headwind, will try to get off the road early and wait it out. On my solo trips where the route planning committee consists of only myself, I often change the plan I made only hours earlier. On my longer trips where an airplane ticket dictates when my last day will be, near the end of my route I might be a couple days early where I am adding more sightseeing or intentionally taking shorter days.
For me it is usually two hours between getting out of my sleeping bag and rolling down the road, but that includes making coffee and breakfast.
I am almost never on the road this early, but I wanted to make the first ferry of the day and had to ride for a while to get to it.
Mosquitos were out early that morning.