I'm trying to match foundation colours!!?

I work for an online store (www.misebeauty.com) and we stock Keyvn Aucoin make up. I am doing a blog post on their Sensual Skin Enhancer product. I want to be able to help people who have never used the product before match it up as best I can to their skin tone. I was wondering if anybody has used this product and know what colour in MAC foundations that they are, if they could let me know what its closest to. (I'm using MAC foundations as reference because it's such a widely available and used brand.) Thanks very much, any help is much appreciated!