My Dad taught me a similar trick when I was learning photography basics from him as a child, slightly different to what you've suggested though: Hold your hand out, fingers stretched straight, palm facing towards you. Tilt your hand towards you (palm towards the ground) just enough so that there is no direct light on the palm and it is evenly lit. Meter with a reflective meter and set to zone V.
We have 'average' Caucasian skin (ie, not pasty but not super tanned) and it used to work just right for us. I don't think I really thought about that technique again after i bought an incident meter though