I put the 24 on Ten Wheel's bike. You will fing that the shift is not as smooth, but it works. A 24-26 will give a 25 inch low gear. That's considered a little high for a tourer. A 24-32 will get 20 inches and closer to a loaded tourers gearing. Lower is even better. If you need lower gears and don't have them you can make yourself miserable pulling a load uphill.
You could even drop the 50 and go for a 48.