I am going to water discount my next batch...nothing big...maybe 5% to see if it helps reduce ash. My question is this: When you use the standard calculation 40% calculation for oils to mold, that assumes the remaining 60% is a combination of lye and water/fluid. Now I'm a pretty smart guy, but I cannot figure how to back into the proper amount of oils to achieve the size bars I need. Maybe I'm overthinking it, but since the standard oil calculation is based on

__volume__while the oil/lye/water calculation is based on weight, I can't reconcile how to back back into the proper oil weight to start with. Nobody likes to end up with great soap but wonky-sized bars.

Obviously, with less water, to achieve a given volume, I will need to increase both the oil and lye volume, but I don't know by how much. Any help? Do any of the the calculators do this math for you?