You can do cream soap recipes on any soap calculator
that lets you create "dual lye" or "hybrid" recipes, meaning recipes that use both KOH and NaOH. Soapee.com is one example as well as the venerable Summer Bee Meadow calc.
Here are some guidelines I've been working on for awhile for developing cream soap recipes. I'm not an expert cream soap maker, so I based these recommendations on a variety of cream soap recipes from reputable sources as well as discussions with a few cream soap makers. I hope Carolyn (cmzaha) and other cream soap makers will let me know if I'm off base with any of my advice -- I reserve the right to correct and update this information. Here goes --
Set the KOH at 80% of the total alkali. The KOH ranges from 75% to 80% in the recipes I evaluated, with 80% being most common.
NaOH makes up the rest of the total alkali. In other words, the combined KOH and NaOH percentages must equal 100%.
Be sure to also set the KOH purity to the correct value for your product. If you do not know the purity, choose 90% as being a typical purity setting.
Set lye concentration at 15% (water:lye ratio of 6.7). Lye concentrations in recipes I looked at range from 10% (water:lye 9.0) to 25% (water:lye 4.0), with 15% being the most common. Important: Use lye concentration or water:lye ratio for best results. Do not
use "water as % of oils".
Set lye discount (superfat) at 15%. Range is 7% to 23% with the most common being 15%.
Choose fats and stearic acid to get the fatty acid profile of the recipe within these ranges --
Combined stearic and palmitic acids should equal 50% to 60% of the total fatty acids. Range is 50% to 70%, with 61% being the average.
Soap will be softer and may gradually separate if these fatty acids are below 50%. Soap will be firmer and may lather poorly if above 70%. Good sources of these fatty acids: lard, palm, tallow, butters (shea, cocoa, etc.), and stearic acid.
Combined lauric and myristic should be about 15% of the total. Range is 7% to 17%, with 13% being the average.
Coconut, palm kernel, babassu.
Ricinoleic acid at 0% to 5% of the total. Range is 0% to 8%, with 5% being the most common.
Castor oil. Not required, but many recipes include it.
Oleic acid for most of the balance.
Olive oil, high oleic oils (HO sunflower, HO safflower, HO canola), sweet almond, etc.
Combined linoleic and linolenic acids should be low to minimize the chance of rancidity. Range is 2% to 12% with the average being 4%.
Stearic acid "supercream" at 2% based on the weight of fats + stearic acid used to make the base soap. Range is 0% to 5%.
Supercream is basically a thickener and texture modifier. More supercream gives a firmer texture, adds a waxy skin feel, and may be more drying to skin. Less supercream gives a softer texture, and the soap may possibly be more prone to eventual separation.
Glycerin at 30% based on the weight of fats + stearic acid used to make the base soap. Range is 0% to 30%, with 30% being the most common.
This glycerin is in addition to the glycerin produced by saponification. It should be added along with the supercream after saponification. It is a processing aid (makes mixing and whipping easier) and a texture modifier.