Before you Spend the Money on a .001g Scale, because they are Pricey, you might want to make 2 Batches of you Favorite e-liquid that are .01g Off in Flavor.
And then see if you can Tell the Difference between the Two? If you Can't, the there is No Need to buy a .001g Scale.
BTW - How were you Planning on Dispensing Liquids on the +/- .001g Level?
Honestly, the ability to go to 0.01g would be more than enough but I'm Mr ocd and love gadgets, why get a good gadget when I can have the ultimate gadget lol