I have had no problems using Ritamulse at rate as low as 2% (bath milk). I am currently working with face products using ~4-%. The only problem I have encountered here is some soaping if I don't get the lipid:emulsifier rate correct, that is if I have too higher lipid value, which should include any oil soluble actives in the cool-down phase. I have tried using as a HLB value and find it to be a little low so 25% of the OP is a pretty good rate to use. Our preservative(Glyceryl Caprylate, Glyceryl Undecylenate) has thinning effect so I have added myristal myristate to give it body but not contribute to viscosity. Our final pH is usualy around 5-4- so we are in the pH range of 5- and given we have not had any separation or curdling suspect this range to very important in avoiding this problem. PS we went to Ritamulse because of soaping with Olivem 1000.