I've done 100% RBO, and 80/20 RBO/castor. Wasn't very fond of them at all, and I use a *lot* of RBO in my normal products. Took a long time to cure, still ended up softer than I liked and lather wasn't all that wonderful. It only has 50% of the oleic acid that olive oil has, so you didn't get the oo slime, you didn't get much of anything. But I'm not into soaps that have to cure a long time - I think I tried it at 2 months and wasn't impressed.