I'm so glad I could offer something. You don't need to be worried about 100 proof nic if you handle it and mix it correctly. Just don't get it on your skin. Use gloves when measuring it. It's really simple math if you go with 100ml batches and 100 mg/ml nic, no spreadsheet or arcane formulas are needed.
If you want to try this approach you can get the lab glassware from RTS Vapes.
100ml Erlenmeyer flasks:
100 ml Erlenmeyer Flask
Rubber stoppers:
Rubber Stopper Size #2
50ml measuring cylinder:
50 ml Measuring Cylinder
Filling syringes and needles:
Filling Syringes and Needles
Now there is a small startup cost for this equipment, but I've found it's well worth it. One Erlenmeyer flask is only $2.39, and I would recommend getting 3 of them to start with. The 50ml measuring (graduated) cylinder is $8.29, and will serve you very well. If you really want to make your own
juice and have it be consistently the same thing every day this is the way to go, or at least it's worked very well for me.
I trust you have already located sources of VG. If not Bulk Apothecary has it at good prices.
Glycerin | Bulk Apothecary
If your experience is anything like mine you will end up buying more Erlenmeyer flasks. I make at least 300ml of
juice at a time to keep it in rotation as it steeps.