Vg is way to thick for 18, 14 works, but I usually use no needle. I've also found putting my vg container in a warm water bath while I'm mixing nic & flavors makes the vg much more manageable, and easier to shake & mix up your final recipe.
I have a few 18 gauge ... Never use them, always 14. They're thin. But they can be used for your flavors & pg.
I also have a few 1ml & 10hypos ... rarely if ever use those, 5ml is my goto it seems. Since I don't use PG (alergic), I don't bother measuring my vg anymore, mix my nic & flavors, then fill the remainder of bottle with vg directly from the vg container.