Brilliant sour Simon. Loving that regal shake. I used the entire peel from a ripe thin skinned lime and it balanced so well with the agave syrup. Up-sized X 1.5 and it was just right.
Next time I'll try with less agave syrup (maybe 1/4 or 1/3 oz). And also, be careful not to put the white part of the zest for doing the regal shake, I thing forgiving this gave a unpleasant bitter taste to my cocktail. Gave it a 4/5 but maybe with these changes it could easily get higher !