You really don't have to be that precise. I'm not, and I'm still alive! I predelute my nic from 60mg to 6 in a wine bottle, then pour into smaller Boston rounds for storage. Then it's just a matter of adding flavors. I started out being uber-precise with syringes, but now I just use old carto condoms (=1ml) as mini-measuring cups (lazy). I mix down directly into old TV bottles, cuz I really like their needle-like droppers.
A lot of people love TV'S BBCC, but me not so much. But then I got spoiled by Sweet-Vapes' BBCC, where you could actually taste the cream cheese and feel the creaminess in your mouth on the exhale. THAT was GOOD!

My experience with TV's: first it was spoiled milk, then baby vomit, then popcorn, then it smelled like feet...I think I had to let it steep for 3-4 weeks!

But their Blueberry Pie was to die for!
Not much into sweet tarts, but I know they're out there. There's a Lorann's additive called "Tart & Sour" that you could play around with too, if you like your flavors puckery.