My preferred bicycle chain lube is ProGold Xtreme (formerly known as Voyager), but I prefer to purchase the larger 16oz. bottle to refill the smaller drip bottles. Pouring chain lube is not something you want to screw up, as it’d be really frustrating to clean up.
To avoid problems I used a T-pin and punched holes in the foil safety cap on the large bottle as seen above. The large hole for pouring is about 3mm x 1mm and the smaller vent is just a simple pinhole. With this setup I can easily pour lube from the large bottle into the smaller ones with little risk of pouring too fast and splashing.
With this setup I’ve even been able to easily refill the ProGold eyedrop-size sample bottles with Xtreme, which is nice because I like to carry one with me when riding.