...
So if everything is 16mg and if I use 1/2 of each with the mixer it's 8+8=16mg.
No, mixing half & half with 0 cuts the mg in half:
16mg+0mg. divided by 2 is 8mg.
I don't have an empty bottle though. Will any bottle work?
I don't know about measuring with syringes. ...Has anyone tried a dropper cause that would work ...
No syringe needed & a dropper would work.
It really sounds like you will need the 16mg for awhile.
Then, since you should reduce slowly you could try a cart reduced 10%
by 9 drops of 16mg+1 drop of 0.
I did a quick search on bottles here & it seems order is the word. I only needed 1 for now so I had a woman do a search in the kitchen & we came up with an Adams food coloring pack of 4 small plastic 1/4 oz. bottles with removable drip tops. I asked which 3 colorings were her favorites & dumped the other one so now there is a mixing carry bottle.

Tested with
e-liquid & they do not spill w/ drip top in place.
Great post, SirVette. Gets me thinking so I can manage this when I get my order.
Please DO correct me if I have the math wrong.