Another overnight oiler here. Though, I only do overnight EVOO treatments when I know that I'll be washing all of my hair the next morning, not just doing a CWC.
    I load up the length of my hair with the EVOO (none on the scalp) and put on a satin sleeping cap so the oil doesn't touch my pillowcases or my skin. It's kind of like sleeping in a soft shower cap.
    Anyway, the next morning, I pull off the cap and run a seamless comb through my hair before getting into the shower. All of the oil comes out in one washing for me. Then I finish my shower as usual...condition, treat, etc.

I have also used EVOO in place of baby oil in the oil spray solution that I use on the ends of my hair, but that makes for some seriously greasy ends, as EVOO is very thick and heavy. Also, I have just dry oiled with it like everyone else here does. Just a teensy amount - like less than a drop - in the palm of your hand, then rub palms together and run them down the length of your hair, concentrating on the ends. My hair is usually pretty greasy after doing this as well, so I just weave it into a braid and forget about it.

EVOO is a very pure oil, so you shouldn't need to mix it with anything unless you're making an oil spray for misting, etc. In which case, you can take just a teeny amount of EVOO and mix it with aloe vera gel or other oils and a whole lot of water, then shake it up.

Anyway, didn't mean to ramble. Hope this helps a bit.