This is nothing more than a suggestion so take it for what it' worth...
I currently buy 100mg/ml Nic and store it in my freezer, I then dilute enough down to 60mg/ml (100% PG) for my working 250ml bottle that I mix with. There are safety precautions that need to be taken seriously when dealing with Nic in high concentration, so please do a little reading
I started DIYin' using 24mg/ml because I figured if I made a mistake (handling or mixing) worse case is I'd get a little headache, no biggie, however a mistake using 100mg/ml could be a different story. Not tryin' to scare you, just offerin' a reasonable suggestion, there a more than enough of us on this thread that are willing to answer questions
I buy my PG and VG separately, primarily for more control of my ratios as I do mix for others and need to take into account the delivery devices they are using and obviously the ratio they prefer if requested. That said a premixed ratio for you would probably work well...
The DIY sub forum has a large amount of very good information, I'm sure you've already took a peek
