I respect your method and am glad that it works for you; and for all the others that prefer to mix with drops. I will NOT try to change your mind or say someone else should not choose the method for themselves.
But, for the sake of those just wetting their feet in the world of DIY, and since you offered one point of view, I will offer another (not "correct" just "different"). I would point out the inherent limitation of drops so the person deciding what might work best for them can be more fully informed.
And that is the ability to accurately
share/communicate your recipes. Drop size is dependent on viscosity, temperature, and type and size of dropper (an 18 gauge syringe needle is going to provide one size drop, a glass eye dropper another, and a plastic dropper bottle yet another). As long as
you don't change anything,
you can replicate the recipe with some consistency. But when I try to replicate it, my drops may be the same, or totally different. (As a side note: I would be curious if your VG based Real Flavors still measure out at 30 drops to the milliliter. Aren't they a lot thicker than your PG based flavors?)
It would be like me sharing a recipe for bread saying "mix together 20 fist-fulls of flower, with 15 cupped palms of water, and a shake of yeast and put it in the oven. You might get a brick, or some awful tasting broth, or some really tasty bread. It all depends on how lucky you are at interpreting my
meaning without a common agreement to the measuring unit.
Also, some ingredients are much more forgiving to over/under measures. Comparing once again to the cooking world, a cookie recipe is going to be a lot more forgiving between a teaspoon and tablespoon of sugar, than it would between a teaspoon and tablespoon of salt even though both ingredients are used in the same recipe. I know this is an overly dramatic example but because we often use so little of each flavor (especially when we mix smaller test batches) it doesn't take a lot of variation to have something taste totally different.
I will be the first to acknowledge that measuring by volume (mL) and measuring by weight (gr) have their potential for error as well. I can misuse a set of measuring spoons, or buy a really lousy set, just as easily as misusing a syringe or scale. But the difference is we are talking about an agreed upon unit of measure (nobody is trying to figure out how big my hand is!

)
That's my take on the subject; and I promise to stop "kicking the dog."