Glycerin content of liquid directly affects the amount of smoke like vapor, but doesn't affect the amount of nicotine delivered. Water is even more of a vapor producer then Glycerin (VG).
This can be easily tested by yourself. Fill a cart with distilled water just like it was a e-juice; vape on it for a few minutes. You will start to see more and more vapor as water replaces your old liquid as the primary source of liquid being vaporized.
Same thing for Glycerin. Easy to test; same procedure as above.
To make JC into any vapor class you want simply add amounts of water/glycerin to your taste. I would suggest putting glycerin n jc into drip bottles, drip jc 1 drop, then glycerin 1 drop, vape, if it has enough vapor, mix jc/glycerin 50/50 as a final product, not enough vapor, drip another vg drop, repeat until affect is desired. Don't flood ur atty though.
For me JC is taste. I don't care about nic quantity or nething else about it. I always add Levy's unflavored vg stuff to it to raise nic and vapor.