Lol. Asking is a good idea. It's Vista vapor.. they are a great company with awesome customer service, I guess it wouldn't hurt to askWell, as I see it, you have two choices. Try the 20% nic (just promise to be careful--run your calculations by us if you're unsure) or try Scott's suggestion to ask your juice vendor for a custom order of 24 mg/ml.
I really don't think that a tiny amount of 20% nic will change your flavor profile dramatically, but what do I know. I always dilute all of my commercial juices because I feel they are too strong in the flavor dept. I also love vaping unflavored.