I mix the same way, Joy, I just do it with tobaccos. I have 8 single flavor tobaccos, in separate 30 ml bottles, well steeped and ready to go. I call those my 'backbone' flavors, or primary tobacco flavors.
I also have maybe a dozen other tobacco, single flavor mixes that I consider complimentary tobacco flavors. They're very good flavors, as well, but I prefer them to be added to primary flavors, in lesser quantities, to give the mix a bit of a 'personality change'.
Then, I have 15 ml, single flavor mixes that I use in very small quantities, if I want to sweeten a tobacco mix. Flavors like Caramel, Toasted Marshmallow, Black Honey, Sweet Coconut, etc.
All 3 'categories' are mixed the same. 60/40 vg/pg base, .4 mg nic, and 5% flavor.
When it's time to fill the tank, I pick one or two of the backbone tobaccos and add a couple of eyedroppers of each, then maybe 1 eyedropper of a complimentary tobacco, then just a tiny bit of one of the sweeteners.
I try and load up the morning tank that I will be taking to work, the night before. Even though all flavors are already well steeped, that one night together allows them to meld a bit. I think that improves the final mix a little bit. I still mix 'em on the fly, as well. I just look over the selection available, pick a combo, fill the tank and go. It's always good. I can't remember the last time I dumped a mix. It's been well over a year.
I have a few 'recipes' that I mix the same, and adhere to the recipe, but 90 - 95% of my mixing is on the fly, tank mixing. Not the conventional way, and may not work for fruits, custards, bakery type of mixes, but it sure kicks ass for tobacco mixes.
@VPC the only taste buds that matter, are your own. If you're having fun experimenting, and discovering things that work for you, and make your taste buds happy, then you're doing it the right way.