80/20 should give you good thick vapor but if you want the densest vapor, 100% VG is the way to go. I can't go above 60% VG on a regular basis personally or it starts coating my throat and vocal cords and making me cough and/or sound funny. I use it on the weekend though. Did you mean 24 ounce or 24 ml? An ounce is roughly 30 ml so it's a big difference.
The easiest way to understand Ohm's law is to play with a calculator
like this and get a feel for how the variables interact. Technically that's an enhanced version of Ohm's law but it's the most useful.
I find thinking of a waterfall is the most useful analogy. The potential is expressed in volts and is how high the waterfall is. The current is expressed in amps and is how much water is flowing over the waterfall per a unit of time. The resistance is expressed in Ohms and is how much area is available for the water to flow through. Lastly, the power is expressed in Watts and is how much force is being exerted by the water as it hits the base of the waterfall. A regulated mod has less water flowing over but from a greater height while the mechs have lots more water falling from a lower height. The force at the base is the same but the way it is achieved is different.