For flesh tones, I generally don't go much darker (if at all) than European flesh if painting Mediterranean or Middle Eastern skin, but use a palette based around a brown base and midtone as opposed to peachy shades. Obviously if you want deeper skin colour you can do that as well, since Islamic armies had a lot of troops from a lot of different regions and of course, people's skin shades differ a lot anyway within the same ethnic group.
I've not used the Scale 75 stuff, but as an example, if I was buying a 3-stage set of paints to use as Arabic flesh, I would probably buy Endurance Brown (base), Wild Beast (mid) and Human Flesh (highlight). This is how my flesh recipe looks on a Bad Squiddo Amazon (although this is a 6-stage flesh tone, with deeper base and lighter highlights, but the principle is the same). See how the skin isn't dark, but you can tell it's not a NW Europe peach skintone, more like a cafe au lait shade.