Planning bottle refills on a long ride
Once a ride is longer than a couple of bottles' worth of mix, you can't carry the whole plan from the start line. You need refill points — and a plan for what goes in each bottle when you get there.
Start with your total carb and fluid demand for the full distance (Carb Fueling calculates both from your route and conditions). Compare that to what your bottles and flasks can actually hold. Any shortfall has to come from somewhere along the way — a shop, a support stop, a water fountain.
Place a "shop stop" at each refill point on your route. Carb Fueling then splits your total carb mix across the stretches between stops, so you know exactly how much powder (your carb mix), water, and products (gels, bananas) to carry — or buy — along the way.
Put stops before a gap gets too big, not after: refilling at 15-20% supply left is a plan, refilling at 0% is a crisis.
For short, well-stocked routes, one refill near the halfway point is often enough. For longer or more remote rides, space stops so no single stretch pushes your bottles past what they can carry.