I've read that it doesn't matter what color you use as long as the value is correct, one of your strengths from your previous post. I have a value-scale taped to the clamp on my easel.
Although I don't know anything about the properties of the Genesis paints, JUMP ON IN!
Also do a search on this Forum on the book
"Art and Fear". Overcoming myriad fears seems to be core to the act of creating anything.