You can decide the size of the container by adding up the volume of all the ingredients and getting the appropriate size.
Common denominator = 12
1/4 gallons = 3/12, 2/3 gallons = 8/12 gallons, 1 & 1/4 gallons = 15/12 gallons.
3/12 gallons + 8/12 gallons + 15/12 gallons = 26/12 gallons.
Therefore you need a container that can hold 3 gallons for the recipe.