Hi, for fair skin tones, I would recommend an 8% and for a medium skin tone, I would recommend a 10%.
The DHA in the product is an active ingredient that reacts with the amino acids and proteins on your clients skin. If a percentage of DHA is used that is too high for them, it can create a tan that looks orange. I would definitely recommend giving the 8 and 10% a go to see if that makes a difference. If you are still concerned about the results and you want to talk it through, I would recommend contacting the nouvatan office who will be more than happy to have a chat about this. Please let me know you need any further help or advice. Xx