In this particular case, I'd look at your emulsifier as a percentage of the total fats and not get too hung up, for the moment, on what % the emulsifier is of the total recipe.
For example, here's Version 1 of my recipe:
Total fats = 60 g
E-wax 16 g
The emulsifier was 16 / 60 * 100 = 26.7% of the total fats
The balance of the recipe was preservative, fragrance, and a bit clay for color -- just 0.5% to 2% of each. I didn't change the proportions of these ingredients from batch to batch, so I basically ignored them for the purposes of tweaking my recipe. I added sugar at about 150% of the weight of my scrub base -- again something I ignored for the purposes of refining the recipe.
Version 1 left my skin feeling too clean and not very lotiony. So I reduced the emulsifier...
Version 2:
Total fats = 60 g
E-wax 14 g
The emulsifier was 14 / 60 * 100 = 23.3% of the total fats
This version with 3.4% less emulsifier left my hands unpleasantly greasy. Yuck. Need more emulsifier so more of the fats wash off, especially in cool water.
Version 3:
Total fats = 78 g
E-wax 18.5 g
The emulsifier was 18.5 / 78 * 100 = 23.7% of the total fats
This version increased the emulsifier by only 0.4%, but the difference was noticeable. I got that just-right lotiony feel when I washed the scrub off with warm water. It left a trace too much fat on my skin when washing with cool water so I think I need a wee bit more emulsifier.
PS -- My scrubs are a firm paste in the jar, no runny oils. Once I warm the paste in my fingers, it starts to soften and loosen up, but it is never runny.
I want the scrub to rinse off nicely, leaving just a pleasant lotiony film of fat on my skin, nothing more. I found the difference is pretty small between a scrub that leaves a greasy, sugary mess on my skin and a scrub that leaves me with that just-right, luxurious lotion-y feel. 
