It seems like there might be another question here and that is how much soap will her recipe make." If I understand that correctly, then you will need to decide how much oils and butters you want. So for instance, you want a recipe, before the lye and water, that is 40 oz of oils. Now, if your recipe calls for 15% coconut oil, you would that that percentage and turn it into a decimal

15% = .15

multiply that .15 by the 40 oz of oil and you get 6 so you would use 6 oz of coconut oil.. Figure each of your oils and butters this way and when you are finished, they all should equal 40 oz.

For example if I wanted to make a castille recipe using 3lbs of oils, I take that 3lbs and turn it to ounces

3x16= 48 oz

my recipe is:

90% oo

10% castor oil

I figure it this way

48 (total oz of my batch) x .90 (the 90% oo turned to a decimal)

48 mutiplied by .10 (10% for the castor)

48x.90= 43.2

48x.1 = 4.8

total 48 oz.

Don't forget then to add the water to that 48 oz of oils.

Now once you figure out how much your mold holds using the formula above, you can design a recipe that will fit and be able to figure out how much each ingredient when given a recipe in percentages.