5 women Illustrated in different personalities

This project is a big risk for me to take on, but I decided to paint it all digital in photoshop. I sketched out the persons separately and then scanned them in. I duplicated the layer of the drawing and then selected the new layer!. I then selected the old drawing layer and made it invisible by clicking the eye on the layer controls. Then I made a new file and added all the people the way I wanted them laid out on the screen, and then I sent a e-mail to my client for approval. He like it but wanted wanted me to add some ruby red rings on there fingers, a table with martini glasses. The back ground I am thinking should be a dark wine red- indian color with a Oil brush texture to convey the idea with ruby red rings theme?

Here is my question to any other artist or designer reading this knowledgeable of photoshop: When I am done with this under painting, how do I save my paint layer as normal, and then the drawing as multiply if I lust want to glaze on my basic toned colors, and then when I want to get be be bolder paint in normal mode? With the options of brush pen selected should I have the settings as other dynamics, Shape dynamics, smoothing and protect texture to make a acrylic or oil painted look?

Remember If you don't ask you will never learn and eveolve! If you are reading this Teacher Jason Seiler maybe you can respond to this request also. I am not embarrassed to ask for help!Thank You again.