Most of my flavorings are in the 20 - 30% range, so 6% PG/Nic would work for all of them from about 30 - 36% PG/70 - 64% VG. With such a small difference between 30/70 and 36/64, you may not even notice the difference. While I have never seen nicotine separate from anything I've ever mixed, I suppose it could happen under the right conditions. Probably a question for ItTechy, our resident chemist. What most people have trouble with with VG is using it in a syringe. Me too! However, I use these tips:
I cut these guys and make an even larger hole, and they work fine with VG now. Also, I like these syringes for larger VG amounts:
These have a very large opening and work great, plus they hold 100 mls.
The main reason I use the VG/Nic, though, is that I mix to about 30% PG much of the time and use a 30/70 ratio. For me, and me alone, mind you, I like being able to do my 100DT tests while observing these parameters. Sometimes, you just get used to certain constants in your mixing journey, because they work for you, again and again, and all things being equal, I try to establish some sort of consistency, as it helps me in many ways in my juice making. There is certainly no one right or wrong way on any of this, and I post this just to share what my own experiences are. I know when I first started vaping, I was 30/70 VG/PG, the exact opposite of what I do now. Because my gear evolved over time, so did my juice, my nicotine content, my preferred flavorings, and my Base ratios. But, find what you like and do that, establish your own rhythms, find out for yourself what works, experiment, and be true to what you like to do, without too much regard for what others experience, as there's no right or wrong way with any of this. Main thing is to just go for it and find your own happy place. Good luck to you!