Like many other things, one size does NOT fit all. You do your research, make your best guess, then adjust from there. For myself ( a chain smoking, ultra light cigarette smoker), I've found that the lower the nicotine, the higher the pg mix I can use and not choke out from the throat hit. As others have noted, certain flavors irritate more or less so I also have to adjust the mix accordingly.
BTW, I also found that my first guess at nicotine level (4mg, the lowest available from my supplier) still gave me an unpleasant nicotine buzz. By starting to mix my own, I lowered that level and found a spot that allows me to vape a lot without the buzz.
Good luck!