Craws for me are the most enjoyable bait I've ever made which stems from my days of tournament fishing. At each event I fished I would walk the bank and turn over rocks in search of getting a craw or two to use in deciding which color trailers I would use for my jigs.
As mentioned above there are so many sub species and color variations making them is never boring. I found the greatest challenge is imitating the molting version which involves semi milky opaque and translucent elements.
I only hand pour so I have options as to how many colors I can integrate in the laminating process needed to create the illusion ranging from 2 to 4 with 3 being the most common. If I'm really energetic I'll pick up a few lake rocks and bring them to the shop for color matching since they molt to their surroundings. I put them in a glass bowl of water then start to match in plastic, I do dibble in making my own skirt material so this is beneficial for that as well.
How I've always viewed making a craw in how I'm going to fish it first and what the fish is going to see while I fish it. 99% of the craws I make have a an opaque white/pink or peach belly/bottom.
The colors I mix and match the most often are Amber, GP, Red, MF Blue Craw and Scuppernong. Flake colors most commonly used .015 black, orange, red, blue, copper, .035 gold, red, copper