While what everyone here is saying is true for a majority of people, I tend to be the opposite. Higher VG juices tend to "junk me up" quick, and dark juices tend to give vape mouth.
The only juice I can vape all day, everyday, is Halo SubZero. It's mix ratio isn't published, but I'd estimate it's about 70% PG / 30% VG, and it's the most intense menthol flavor on the market.
The best recommendation I can advise, is to try and "vape through it" and see how things go after a couple of weeks and drinking plenty of water daily. A lot of times, our bodies needs to adjust to not smoking, and vaping is something else entirely to get used to. Experiment with different flavors, and keep at it. Don't be afraid to come here and ask questions. We've all been right where you are now