I'm not sure I entirely agree on what Tiana said. While I do think the difference between 2 and 3 is more subtle than the jump from 1 to 3, there is still a big difference in the detail level.

As for my own approach, I personally make the biggest difference between colour levels in my own work. As you can see in my portfolio, I roughly divide my maps between greyscale, partial colour and full colour. I've also made the choice to set up parchment maps as a separate category on my website (even though they are just partial colour maps), just because it's by far the most popular option among my clients.

I also have this image on hand that I can send to clients when negotiating a new project, if they don't have an idea of their desired colour level from the start:
Colour_examples.jpg

I don't know how well this would translate to your work, but having a portfolio separated into different map categories might work for you as well.