I had a homebrew book out the library and it said to use 2kg of honey in a gallon demijohn. I guess it depends how strong tasting you want it, because about 1kg of honey is all that's needed for the yeast to exhaust itself and the rest is sweetness in the final product. It also said there's no nutrient in honey for yeast, so to get the alcohol levels up you need to use a teaspoon of yeast nutrient.