What color should I make the company hero’s loincloths and capes?

I'm a new painter, and for my first box I picked up the 40k iron halo strike force. I'm painting my army as iron hands, I have the colors for most things picked out, but I'm not really sure on what to do for the inner sand color of the capes and the loincloths. I'll probably be using chaos black as my base coat so I think contrast paints are off the table unless I put another base over top of the black.
I'm willing to buy 2-3 different colors if needed.