I came to really like the TV Macchiato. Of course, if you order from TV, try some German Chocolate Cake -- not a coffee, just something everyone should try
For TV, you can either just order the liquid with nic, at the nic level you want, or order a higher level nic and some of their doubler -- same flavor, just 0 nic.
Example. I buy their GCC at 36 mg strength, plus a two ounce (60 ml) bottle of doubler. TV includes a spare (empty) bottle, just for mixing.
If I want 18 mg strength, I put equal amounts of the 36 mg and 0 mg into the bottle. If I want 12 mg strength (I chain-vape it, at work), I put in one part 36 mg and two parts 0 mg doubler.
I just eyeball it for this -- use a black Sharpie, put marks on the side of the plastic bottle. About 1/2" up from the bottle bottom a mark for the 36, then a mark 1" further up for when I add the doubler, and I end up with pretty close to 12 mg.
Shake the bottle after you've put the two in (to mix the two liquids together), and you're ready to go.