Nice oil bottles!
FWIW, the flattened tip shown in the last image will pick up the greatest amount of oil. I was a student at St Paul College in watchmaking/micromachining in the 1990's, and learned to use these dip type oilers.
The greatest amount of oil the tip will collect is when it is quickly withdrawn from the pool of oil. Withdrawing slowly results in less oil adhering to the tip. And the smaller the tip, the less it will pickup. The "arrowhead" version will pickup the most. A needle point will pick up almost nothing.
These little oilers are great for getting lubricant on tumblers, flys, frizzen rollers. If too much, cold weather can really slow things down. These oilers can make just the right amount.