When talking about RUG + WVO or #2 and WVO, I do not think you need anything. Even stuff that I blended 6+ years ago, and kept in a clean jar as an experiment has remained "blended.". Maybe a hint of something settling, but I am thinking that's just my grease. Even just WVO from 5 years ago which was cleaned in a centrifuge did settle a hint of something. So, for the above, I am thinking they just blend and bond together.

As for any emulsifiers, I am thinking that would create some sort of unwanted by-product, but I got a "C" in college chemistry so count me out on the complex stuff.