I’ve never had the rapid drops, what I get is it sucking up into the space around the dropper and delivering a massive dollop, or occasionally pulling from the tip of the dropper and then falling from the edge of the bottle lip, although this is much less common.
But I’ll hunt-out that vent, clean the gap and try it again. Thanks. 
That’s pretty interesting, I’m going to have to check it out myself. Although I usually avoid roller balls because they rip out my arm hair, its hard to find enough open real estate. hah /tmi
what do you clean it with that wont contaminate it
Hydrofluoric acid.
But not really. Probably some sort of alcohol. Maybe witch hazel or hydrogen peroxide.
I used sterile gauze to wipe the top of my A314 bottle clean.
I prefer the squeeze dropper for oil products. It’s the only way I’ve ever been able to get exactly what I want every time.
Roll-ons are convenient, but I never really know how much I’m getting when I roll it on.
Shake the bottle for like 15-30 seconds. I also will roll it around in my hands a bit to warm the bottle up, especially now that its winter. Then I make goo goo eyes at it, tell it how sexy it is, promise to buy it dinner and when it gives up the goods I ignore it until I need it again.
But seriously, shake it and roll it around in your warm hands.
I totally agree with the Dropper way of doing it, especially with oil based products. Its sold at the store under mixing supplies.
15 mL Cobalt Bottle with Dropper Top :: Mixing Supplies :: Androtics Direct
You will get exact dosage, and you can return unused back to bottle.
Also, I recall seeing somewhere that there are some Sprayers for fragnance oils, although I am not sure how effective they are with A314. I can try this myself, if there is enough interest from others.
On the other hand, having a rubber dropper or sprayer on the bottle won’t help make A314 be portable in a to-go form, since the bottle today is easily carried with other to-gos.
Just my two cents