I'm looking to use a syringe with a shorter needle, similar to what you get on a pen- 3/4/5mm etc. They do exist, however I'm unsure what the minimum length a needle needs be in order to pierce through the cap to draw up your dose. On a pen you are obviously not drawing up with that needle so it doesn't matter, but on a syringe it does. Is anyone aware of the thickness of the caps on the compounds (and Bac water as well) ? What is the shortest one could get away with while still being able to draw up?