How long do the A314 oil drops last throughout the day before you should be reapplying? Or are they considered a full-day effect?
How much should you be using? I just got mine a week ago and I’ve been using 1 drop behind each ear (rubbing the oil all over the back of my ears) for a total of 2 drops.
Depending on temp/humidity A314 oil should last 6-8 hours on a normal application. So it will easily carry you through the working day in a comfortable environment. Less if its hot and sweaty.
However, if you apply over a light application of lotion, you will get a good couple of hours more per application because the lanolin makes a decent barrier to skin absorbtion and slows degradation from skin bacteria. Any decent quality hand lotion will do.
Personally, I wouldn’t rub it in too hard - spread it out lightly and also consider your temples - just in front of your ears. A good app point with maybe a better blood flow than behind the ears.
As for dose, you have surely been around long enough to know we can’t tell you that? YOU have to do some legwork to find your sweet spot for the various situations in your life. 
I agree with Mobo, for me it lasts for more than 8 hrs as my testing ground is work environment and usually apply behind the ear.. i will try on temple and let you know guys.. also with some light lotion