Went with T.C.'s suggestion regarding agave and thought it a good tip. First one was well balance and tasty (and sooo easy going down). I upped the tequila to a full shot and found it was still good with just a little more kick and, oh, look at the pretty Christmas lights. . .
Hi Bret. You'll find an explanation of what a dash and drop is if you click "measures & measuring" under the recipe above. Then, it is a case of hitting the calculator. Although specific gravities vary, when batching, I measure by weight using 1 ml = 1 gram. I zero the scales with the container and then built on the weight, adding the weight of each successive ingredient.
I found this got way better with just a quarter ounce of agave syrup. Without it, I was missing a lot of the flavour, particularly of the tequila. Very interesting concept, and one I'll be fussing over trying to perfect for myself.