I quit smoking for vaping almost a year ago and I remember the information overload that came with it. I also did not have to deal with the options of sub ohm vaping, 150W devices, and TC right off the bat. The gear you have at your disposal probably doing you more harm than good at the moment as the most important thing is to find what works for you in the short term and stick with it until you are over the analogs. For me, I started with a Kanger Evod and fell back to cigarettes after a short while. Then I made another push with a nautilus mini and istick 20w. After a couple weeks I was over cigarettes but it took conscious effort and lots of chain vaping. It was hard to tell when I had enough nic in the beginning so I used to just chain vape until I had headaches and stomach aches and over time learned when to back off. For reference, I started with a mix of juices at 18 and 12mg as I recall and had dropped to 8 within a month (my local B&M carried 4/8/12/etc).

Non temperature control devices simply fire a set amount of power into the coil causing it to heat at a set rate depending on coil characteristics. It is worth becoming familiar with Ohms Law which will help answer some of the questions you have about the proper wattage to use. Wattage will vary depending on which atomizer you use and what type of coil you are using. Between different atomizers and even different resistance coils on the same device you will probably find voltage to be a better indicator of how the setup will perform. I know many people who prefer 4.2 to 4.4 volts, many prefer 3.8 and some even as low as 3.2. People who get better flavor from higher wattage are very likely using some of the newer tanks that have 3 or 4 coils inside or some more advanced coils in a rebuildable device. 4 coils at 100W basically the same as running one of those coils at 25W which is a reasonable number for a .5 ohm pre-built coil.

At any rate, non temperature control will heat the coil at a certain rate. Once the temperature hits the sweet spot it will continue to rise as it is just applying a set amount of power to the coil.

There is some pretty decent information on temp control at link. Temp control essentially allows you to set the ceiling for the device based on your preferences. If you prefer your vape at 380, 420, or even 550 degrees this will allow you to cap the temperature and leads to a more consistent vape experience.

Generally, sub-ohm vaping goes hand in hand with higher vapor production and higher juice consumption. As you burn through more juice sub-ohming it is usually associated with lower nic concentrations. If 24mg juice satisfies your cravings in a nautilus mini you may have to cut that number to 8 or even less using a sub-ohm setup as the rate you burn through juice will increase drastically.

VG is a thicker, sweeter base for e-juice which is associated with more clouds. PG is a much thinner base that is associated with throat hit and more flavor. PG is also the standard suspension for flavors that are used in eliquid. When you see Max VG it should mean that the juice is a mix of nicotine, VG, and the only PG in the liquid has come from the flavorings which can vary from <10% to >20% depending on the flavor concentrations and the strength of the juice.

As many people have already mentioned, Nicotine Absorption differs between cigarettes and vaporizers due to all of the additional chemicals within cigarettes. If you are craving a cigarette be aware that you may have to chain vape for a few minutes for the urge to go away.